Set icon in Avalonia

2025-11-03 23:35 UTC gpt-5-thinking Open in ChatGPT ↗

Here are the common ways to set icons in an Avalonia (C#) app, from the window/title-bar icon to the actual app/exe icon when packaged.

1) Window (title-bar/taskbar) icon

Use an embedded asset and point the Window.Icon to it.

XAML

<!-- MainWindow.axaml -->
<Window
    xmlns="https://github.com/avaloniaui"
    x:Class="MyApp.MainWindow"
    Icon="/Assets/app.ico">
    <!-- ... -->
</Window>

Code-behind (alternative)

using Avalonia.Platform;
using Avalonia.Controls;
using System;

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        // Works with .ico, .png, etc. (ICO recommended for Windows)
        this.Icon = new WindowIcon(
            AssetLoader.Open(new Uri("avares://MyApp/Assets/app.ico")));
    }
}

Don’t forget:

Put the file (e.g., Assets/app.ico) in your project.
Set its Build Action to AvaloniaResource (not Content).
Include multiple sizes in the .ico (16, 24, 32, 48, 256px is a good set).

2) System tray icon (if you use one)

<!-- App.axaml -->
<Application xmlns="https://github.com/avaloniaui">
  <Application.Styles>
    <!-- your styles -->
  </Application.Styles>

  <Application.TrayIcons>
    <TrayIcon Icon="/Assets/app.ico"
              ToolTipText="MyApp"
              IsVisible="True" />
  </Application.TrayIcons>
</Application>

3) App/executable icon (what Windows shows for the .exe)

This is separate from the window icon. Add to your .csproj:

<PropertyGroup>
  <!-- Use a multi-size .ico -->
  <ApplicationIcon>Assets\app.ico</ApplicationIcon>
</PropertyGroup>

4) Platform packaging notes

Windows: the <ApplicationIcon> above sets the .exe icon and the Start Menu icon when you publish.
Linux: desktop environments read icons from a .desktop file. When you package, make sure that file’s Icon=myapp points to an installed PNG (often placed in /usr/share/icons or /usr/share/pixmaps). Provide a square PNG (e.g., 256×256).
macOS: app bundles use .icns. When you create a macOS bundle, include an .icns and set the bundle’s CFBundleIconFile to it. (Most Avalonia packaging templates expose a place to drop this in; convert from PNGs using iconutil.)

Quick checklist

Icon file added to Assets/
Build Action = AvaloniaResource
Window Icon="/Assets/app.ico" set (or in code)
Windows only: <ApplicationIcon> set in .csproj
Packaging: provide platform-appropriate formats (.ico / .png / .icns)

If you paste your project structure (or say which platforms you’re targeting), I can tailor the exact snippet for you.

Here’s a solid, size-focused single-file publish command you can drop in. Swap the RID for your target OS/CPU.

Windows (x64)

dotnet publish -c Release -r win-x64 ^
  -p:PublishSingleFile=true ^
  -p:SelfContained=true ^
  -p:PublishTrimmed=true ^
  -p:EnableCompressionInSingleFile=true ^
  -p:IncludeNativeLibrariesForSelfExtract=false ^
  -p:IncludeAllContentForSelfExtract=false

Linux (x64)

dotnet publish -c Release -r linux-x64 \
  -p:PublishSingleFile=true \
  -p:SelfContained=true \
  -p:PublishTrimmed=true \
  -p:EnableCompressionInSingleFile=true \
  -p:IncludeNativeLibrariesForSelfExtract=false \
  -p:IncludeAllContentForSelfExtract=false

macOS (Apple Silicon)

dotnet publish -c Release -r osx-arm64 \
  -p:PublishSingleFile=true \
  -p:SelfContained=true \
  -p:PublishTrimmed=true \
  -p:EnableCompressionInSingleFile=true \
  -p:IncludeNativeLibrariesForSelfExtract=false \
  -p:IncludeAllContentForSelfExtract=false

Notes / trade-offs

Trimming: PublishTrimmed=true cuts size. Avalonia generally supports this, but if you see missing resources/reflection issues, remove that flag or add -p:TrimMode=partial.
Compression: EnableCompressionInSingleFile=true shrinks the file a bit with a minor startup hit.
Extractionless: The two Include*ForSelfExtract=false keep everything bundled without unpacking to disk.
Performance option: Add -p:PublishReadyToRun=true for faster startup (larger binary).
Extra size cut (optional): -p:InvariantGlobalization=true saves a few MB but disables per-culture collation/formatting.

If you tell me your exact target(s), I’ll tailor the command and flags (e.g., ReadyToRun for Windows only, or culture support kept on).

This usually boils down to PATH/env issues between macOS, your shell, and how Rider launches its Terminal. Here’s a quick fix path 👇

Fast checks

Is .NET SDK installed?
Terminal window
```
dotnet --info
```
If it errors in macOS Terminal too, install:
- Microsoft installer: https://dotnet.microsoft.com/download
- or Homebrew: brew install --cask dotnet-sdk

Where is dotnet actually located? Try the common paths:

/usr/local/bin/dotnet --info
/usr/local/share/dotnet/dotnet --info
/opt/homebrew/bin/dotnet --info           # Apple Silicon Homebrew
/opt/homebrew/share/dotnet/dotnet --info

If any of those work, it’s a PATH problem inside Rider’s terminal.

Make Rider’s terminal see your PATH

Rider doesn’t always start a login shell, so your PATH from ~/.zprofile may not load.

In Rider: Settings/Preferences → Tools → Terminal
- Shell path: /bin/zsh (or your shell)
- Run command as login shell: ✅ (enable)
- Restart the terminal tab.

Ensure your PATH is set in the right file for zsh:

Put one-time PATH exports in ~/.zprofile (login shells)
Put interactive tweaks/aliases in ~/.zshrc Add (adjust if your dotnet path differs):

# Microsoft installer (typical)
[[ -d /usr/local/share/dotnet ]] && export PATH="/usr/local/share/dotnet:$PATH"

# Homebrew on Apple Silicon
[[ -d /opt/homebrew/bin ]] && export PATH="/opt/homebrew/bin:$PATH"
[[ -d /opt/homebrew/share/dotnet ]] && export PATH="/opt/homebrew/share/dotnet:$PATH"

Then restart Rider (so it picks up your login env), or enable the “login shell” option above.

Verify inside Rider’s terminal

echo $SHELL
echo $PATH
which dotnet
dotnet --info

Rider’s .NET settings (optional but helpful)

Settings/Preferences → Build, Execution, Deployment → .NET Installations
Add the exact CLI path if Rider didn’t auto-detect it (e.g., /usr/local/share/dotnet/dotnet or /opt/homebrew/share/dotnet/dotnet).

Apple Silicon / Rosetta gotcha

If you run Intel Rider under Rosetta, it may expect an x64 .NET SDK.
Prefer Apple Silicon Rider + arm64 .NET SDK. If you must use Rosetta, install an x64 SDK too.

If it still says “not found”

The symlink might be missing. Create it (adjust source if needed):

sudo ln -s /usr/local/share/dotnet/dotnet /usr/local/bin/dotnet
# or for Homebrew:
sudo ln -s /opt/homebrew/share/dotnet/dotnet /opt/homebrew/bin/dotnet

Then re-open Rider and try again.

If you paste your which dotnet and dotnet --info outputs (from both macOS Terminal and Rider’s terminal), I’ll pinpoint the exact step to fix.

That ILLink error means the trimmer can’t find a Main entry point in your app assembly. Most commonly it happens when the project is accidentally a class library (no Main) or your Program.cs/Main got removed/renamed.

Here’s how to fix it fast.

1) Make sure the project outputs an executable

In your .csproj:

<PropertyGroup>
  <OutputType>WinExe</OutputType>   <!-- or Exe; WinExe hides console on Windows -->
  <TargetFramework>net9.0</TargetFramework>
</PropertyGroup>

If OutputType is missing or set to Library, the trimmer reports IL1034.

2) Ensure you have a proper `Main` method

Typical Avalonia Program.cs (works on macOS too):

using Avalonia;
using Avalonia.ReactiveUI;

internal static class Program
{
    public static void Main(string[] args) =>
        BuildAvaloniaApp().StartWithClassicDesktopLifetime(args);

    public static AppBuilder BuildAvaloniaApp()
        => AppBuilder.Configure<App>()
                     .UsePlatformDetect()
                     .LogToTrace()
                     .UseReactiveUI();
}

File should compile into the same assembly as your app (not another project).
Namespace/class name doesn’t matter, but the assembly must contain a single entry point.

3) Re-try publish without trimming (sanity check)

If this works, the issue was purely “no Main” from the trimmer’s perspective.

dotnet publish -c Release -r osx-arm64 -p:PublishSingleFile=true -p:SelfContained=true

4) Then add trimming back (optional)

If you want size savings, trim with a safer mode:

dotnet publish -c Release -r osx-arm64 \
  -p:PublishSingleFile=true -p:SelfContained=true \
  -p:PublishTrimmed=true -p:TrimMode=partial

5) Other gotchas

If you see only …/InvoiceGeneratorDesktop_v2.dll in bin/…/osx-arm64/, that’s normal for framework-dependent builds. For SelfContained + SingleFile, you’ll get a single native file (no .dll as the thing you run).
If you have multiple startup projects in a solution, make sure you’re publishing the UI project (the one with Main), not a shared library.

If you paste your .csproj top <PropertyGroup> and Program.cs, I’ll spot the exact mismatch.

NETSDK1099 means the project you’re publishing is being treated as a library (no app host), so “single file” isn’t allowed. Two common causes:

you’re accidentally publishing the library project, or
your exe project isn’t marked as an executable (missing OutputType/app host).

Here’s how to fix it quickly.

1) Make sure you publish the exe project

Run publish against the executable .csproj explicitly (don’t target the solution or the library):

# macOS (Apple Silicon)
dotnet publish path/to/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.csproj \
  -c Release -r osx-arm64 \
  -p:PublishSingleFile=true -p:SelfContained=true

# Windows (x64)
dotnet publish path/to/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.csproj ^
  -c Release -r win-x64 ^
  -p:PublishSingleFile=true -p:SelfContained=true

If you use Rider/VS, ensure the publish target is the executable project, not the class library.

2) Verify the exe project is actually an executable

Open InvoiceGeneratorDesktop_v2.csproj (the app project) and ensure:

<PropertyGroup>
  <TargetFramework>net9.0</TargetFramework>
  <OutputType>WinExe</OutputType>   <!-- or Exe -->
  <UseAppHost>true</UseAppHost>     <!-- ensures a native launcher -->
  <!-- optional size/perf flags -->
  <!-- <PublishTrimmed>true</PublishTrimmed>
  <TrimMode>partial</TrimMode>
  <EnableCompressionInSingleFile>true</EnableCompressionInSingleFile> -->
</PropertyGroup>

<ItemGroup>
  <ProjectReference Include="..\MyLibrary\MyLibrary.csproj" />
</ItemGroup>

And in the library project, make sure you don’t set any publish/single-file flags:

<!-- MyLibrary.csproj -->
<PropertyGroup>
  <TargetFramework>net9.0</TargetFramework>
  <OutputType>Library</OutputType>
  <IsPackable>false</IsPackable>
</PropertyGroup>

Avoid putting <PublishSingleFile> in a solution-wide Directory.Build.props; if you did, remove it or wrap it in a condition so it applies only to the exe project:

<PropertyGroup Condition="'$(MSBuildProjectName)' == 'InvoiceGeneratorDesktop_v2'">
  <PublishSingleFile>true</PublishSingleFile>
  <SelfContained>true</SelfContained>
</PropertyGroup>

3) Sanity checks (super helpful)

From the app project folder:

# Check what MSBuild thinks:
dotnet msbuild -getProperty:OutputType
dotnet msbuild -getProperty:UseAppHost

# Ensure your entry point exists:
grep -R "static void Main" -n ./  # or search Program.cs if on macOS

If OutputType ≠ WinExe/Exe or UseAppHost ≠ true, fix the csproj.

4) Add back size/perf flags once it publishes

When the basic single-file works, you can add:

-p:PublishTrimmed=true -p:TrimMode=partial (watch for reflection issues)
-p:EnableCompressionInSingleFile=true
Optionally -p:PublishReadyToRun=true (faster startup, larger file)

If you paste the top <PropertyGroup> from both .csproj files, I’ll pinpoint exactly why the app ended up as a library during publish.

NETSDK1099 means the project you’re publishing is not an executable (MSBuild thinks it’s a Library), so single-file isn’t allowed. Fix it with this checklist:

Quick fixes

A. Make sure you’re publishing the EXE project (not the library).

# macOS (Apple Silicon)
dotnet publish path/to/YourExeProject/YourExeProject.csproj \
  -c Release -r osx-arm64 \
  -p:PublishSingleFile=true -p:SelfContained=true -p:UseAppHost=true

# Windows (x64)
dotnet publish path/to/YourExeProject/YourExeProject.csproj ^
  -c Release -r win-x64 ^
  -p:PublishSingleFile=true -p:SelfContained=true -p:UseAppHost=true

B. In the EXE project’s .csproj, ensure it’s an executable with an app host:

<!-- YourExeProject.csproj -->
<PropertyGroup>
  <TargetFramework>net9.0</TargetFramework>
  <OutputType>Exe</OutputType>          <!-- or WinExe -->
  <UseAppHost>true</UseAppHost>          <!-- required for single-file -->
  <!-- optional -->
  <!-- <PublishTrimmed>true</PublishTrimmed>
  <TrimMode>partial</TrimMode>
  <EnableCompressionInSingleFile>true</EnableCompressionInSingleFile> -->
</PropertyGroup>

<ItemGroup>
  <ProjectReference Include="..\YourLibrary\YourLibrary.csproj" />
</ItemGroup>

C. In the LIBRARY project, do not set single-file/publish flags:

<!-- YourLibrary.csproj -->
<PropertyGroup>
  <TargetFramework>net9.0</TargetFramework>
  <OutputType>Library</OutputType>
  <IsPackable>false</IsPackable>
</PropertyGroup>

D. Check for solution-wide flags forcing libraries to single-file.
If you have Directory.Build.props/targets with PublishSingleFile or SelfContained, scope them to the EXE only:

<!-- Directory.Build.props -->
<PropertyGroup Condition="'$(MSBuildProjectName)' == 'YourExeProject'">
  <PublishSingleFile>true</PublishSingleFile>
  <SelfContained>true</SelfContained>
  <UseAppHost>true</UseAppHost>
</PropertyGroup>

Diagnose fast

From the EXE project folder run:

dotnet msbuild -getProperty:OutputType
dotnet msbuild -getProperty:UseAppHost
dotnet msbuild -getProperty:PublishSingleFile

OutputType must be Exe/WinExe
UseAppHost must be true
PublishSingleFile should be true only on the EXE project

If any of those are wrong, fix the .csproj or move mis-scoped props out of the library.

If you paste the top <PropertyGroup> from both .csproj files (and any Directory.Build.props), I’ll pinpoint exactly what’s triggering NETSDK1099.

You’ve built a single-file exe, but macOS needs a .app bundle. Single-file just packs your bits; it doesn’t create the bundle structure (MyApp.app/Contents/...). Do one of these:

Option A — Create a .app directly via `dotnet publish`

From the executable project (not the library), run:

# macOS (Apple Silicon)
dotnet publish ./InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.csproj \
  -c Release -r osx-arm64 \
  -p:UseAppHost=true \
  -p:MacOSAppBundle=true \
  -p:PublishSingleFile=true \
  -p:SelfContained=true \
  -p:EnableCompressionInSingleFile=true \
  -p:IncludeNativeLibrariesForSelfExtract=false \
  -p:IncludeAllContentForSelfExtract=false

This produces:

./InvoiceGeneratorDesktop_v2/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.app

Tip: you can also set bundle metadata in the .csproj:

<PropertyGroup>
  <CFBundleIdentifier>com.yourco.InvoiceGenerator</CFBundleIdentifier>
  <CFBundleName>Invoice Generator</CFBundleName>
  <CFBundleDisplayName>Invoice Generator</CFBundleDisplayName>
  <CFBundleShortVersionString>2.0.0</CFBundleShortVersionString>
  <CFBundleVersion>200</CFBundleVersion>
</PropertyGroup>

(If your SDK doesn’t honor MacOSAppBundle, jump to Option C.) citeturn1search2

Option B — Keep your Windows single-file publish

dotnet publish ./InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.csproj ^
  -c Release -r win-x64 ^
  -p:PublishSingleFile=true ^
  -p:SelfContained=true ^
  -p:EnableCompressionInSingleFile=true ^
  -p:IncludeNativeLibrariesForSelfExtract=false ^
  -p:IncludeAllContentForSelfExtract=false

Option C — Use Avalonia’s Parcel packager (nice DX, also makes DMG/ZIP)

Parcel will publish, bundle into .app, (optionally) sign & notarize, and can build Windows installers too.

# install the tool (requires Avalonia Accelerate license)
dotnet tool update -g Avalonia.Parcel

# quick pack to DMG (or ZIP) for Apple Silicon
parcel pack MyApp.parcel.xml -r osx-arm64 -p dmg
# or to produce a plain .app bundle:
parcel step publish ./ ./out -r osx-arm64 -p MyApp.parcel.xml
parcel step bundle-mac ./out ./InvoiceGenerator.app -p MyApp.parcel.xml

Parcel also supports merging x64 + arm64 into a universal app if you build both architectures first and run parcel step merge-mac, then bundle-mac. citeturn2view0

Common pitfalls to avoid

Publishing the library: NETSDK1099 happens if you publish the class library. Always publish the exe project.
Missing app host: ensure UseAppHost=true so the bundle has a native launcher. citeturn1search2turn0search17
Expecting single-file to make a .app: it doesn’t; you still need bundling (Option A/C). citeturn1search2

Want me to check your .csproj and spit out the exact commands (Windows + macOS, with icons and bundle IDs)? Paste the top <PropertyGroup> of your exe project and I’ll tailor it.

You can have your .app bundle built automatically right after dotnet publish using an MSBuild AfterPublish target that runs a tiny bash script.

Drop this into your executable project’s .csproj (adjust paths for your icon, bundle id, etc.):

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net9.0</TargetFramework>
    <OutputType>WinExe</OutputType>
    <UseAppHost>true</UseAppHost>

    <!-- single-file, self-contained publish -->
    <PublishSingleFile>true</PublishSingleFile>
    <SelfContained>true</SelfContained>

    <!-- bundle metadata -->
    <CFBundleIdentifier>com.yourco.InvoiceGenerator</CFBundleIdentifier>
    <CFBundleName>Invoice Generator</CFBundleName>
    <CFBundleDisplayName>Invoice Generator</CFBundleDisplayName>
    <CFBundleShortVersionString>2.0.0</CFBundleShortVersionString>
    <CFBundleVersion>200</CFBundleVersion>

    <!-- where your .icns lives -->
    <MacIconPath>Assets/AppIcon.icns</MacIconPath>
  </PropertyGroup>

  <!-- Build the .app right after publish (macOS RIDs) -->
  <Target Name="BundleMacApp"
          AfterTargets="Publish"
          Condition="'$(RuntimeIdentifier)' == 'osx-arm64' Or '$(RuntimeIdentifier)' == 'osx-x64'">
    <PropertyGroup>
      <AppName>$(AssemblyName)</AppName>
      <PublishOut>$(PublishDir)</PublishOut>
      <AppBundle>$(PublishOut)$(AppName).app</AppBundle>
      <MacOSDir>$(AppBundle)/Contents/MacOS</MacOSDir>
      <ResDir>$(AppBundle)/Contents/Resources</ResDir>
      <Plist>$(AppBundle)/Contents/Info.plist</Plist>
      <!-- The published native launcher name equals $(AssemblyName) -->
      <Launcher>$(PublishOut)$(AssemblyName)</Launcher>
    </PropertyGroup>

    <!-- Create bundle folders -->
    <Exec Command="bash -c 'set -e
      rm -rf &quot;$(AppBundle)&quot;;
      mkdir -p &quot;$(MacOSDir)&quot; &quot;$(ResDir)&quot;'" />

    <!-- Copy launcher into Contents/MacOS and make it executable -->
    <Exec Command="bash -c 'set -e
      cp &quot;$(Launcher)&quot; &quot;$(MacOSDir)/$(AppName)&quot;;
      chmod +x &quot;$(MacOSDir)/$(AppName)&quot;'" />

    <!-- Copy icon (optional but recommended) -->
    <Exec Condition="Exists('$(ProjectDir)$(MacIconPath)')"
          Command="bash -c 'cp &quot;$(ProjectDir)$(MacIconPath)&quot; &quot;$(ResDir)/AppIcon.icns&quot;'" />

    <!-- Write Info.plist -->
    <Exec Command="bash -c 'cat &gt;&quot;$(Plist)&quot; &lt;&lt;PLIST
<?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?>
<!DOCTYPE plist PUBLIC &quot;-//Apple//DTD PLIST 1.0//EN&quot; &quot;http://www.apple.com/DTDs/PropertyList-1.0.dtd&quot;>
<plist version=&quot;1.0&quot;>
<dict>
  <key>CFBundleIdentifier</key><string>$(CFBundleIdentifier)</string>
  <key>CFBundleName</key><string>$(CFBundleName)</string>
  <key>CFBundleDisplayName</key><string>$(CFBundleDisplayName)</string>
  <key>CFBundleExecutable</key><string>$(AppName)</string>
  <key>CFBundlePackageType</key><string>APPL</string>
  <key>CFBundleShortVersionString</key><string>$(CFBundleShortVersionString)</string>
  <key>CFBundleVersion</key><string>$(CFBundleVersion)</string>
  <key>LSMinimumSystemVersion</key><string>11.0</string>
  <key>LSApplicationCategoryType</key><string>public.app-category.productivity</string>
  <key>NSHighResolutionCapable</key><true/>
  <key>NSPrincipalClass</key><string>NSApplication</string>
  <key>CFBundleIconFile</key><string>AppIcon</string>
</dict>
</plist>
PLIST'" />

    <!-- (Optional) codesign if SIGN_IDENTITY is provided: msbuild /p:SIGN_IDENTITY="Developer ID Application: Your Name (TEAMID)" -->
    <Exec Condition="'$(SIGN_IDENTITY)' != ''"
          Command='bash -c "codesign --force --deep --options runtime --sign &quot;$(SIGN_IDENTITY)&quot; &quot;$(AppBundle)&quot;"' />

    <!-- (Optional) create a DMG if CREATE_DMG=true: msbuild /p:CREATE_DMG=true -->
    <Exec Condition="'$(CREATE_DMG)' == 'true'"
          Command='bash -c "hdiutil create -fs HFS+ -srcfolder &quot;$(AppBundle)&quot; -volname &quot;$(AppName)&quot; &quot;$(PublishOut)$(AppName).dmg&quot;"' />
  </Target>
</Project>

How to use it

Ensure you’re publishing the executable project (not the library).
Run:

dotnet publish -c Release -r osx-arm64

You’ll get:

bin/Release/net9.0/osx-arm64/publish/YourApp.app
# (and optionally YourApp.dmg if CREATE_DMG=true)

Notes & tips

This works great with your current setup (exe + library). The library is included automatically via the publish output; the script just wraps the published bits into a proper .app.
The script assumes a self-contained publish with an app host (UseAppHost=true), which you already have set.
If you prefer, you can skip the custom script and let the SDK do it by adding -p:MacOSAppBundle=true to your publish, but the script gives you full control (icons, DMG, codesign, etc.).
For Windows, you don’t need a post-build step for a “.app”; keep using your single-file publish (or use an installer tool like WiX/Squirrel/MSIX later).

If you want, I can tweak the target to also notarize when you provide APPLE_ID, TEAM_ID, and an App Store Connect API key.

it originally looked like this. adjust propeerly

WinExe net9.0 enable true Invoice Generator Uncharted Limbo Collective

<PropertyGroup>
    <ApplicationManifest>app.manifest</ApplicationManifest>
</PropertyGroup>

<PropertyGroup>
    <CFBundleIdentifier>com.ulc.InvoiceGenerator</CFBundleIdentifier>
    <CFBundleName>Invoice Generator</CFBundleName>
    <CFBundleDisplayName>Invoice Generator</CFBundleDisplayName>
    <CFBundleShortVersionString>2.0.0</CFBundleShortVersionString>
    <CFBundleVersion>200</CFBundleVersion>
</PropertyGroup>

<ItemGroup>
    <PackageReference Include="Avalonia.Controls.DataGrid" Version="11.3.8" />
    <PackageReference Include="Avalonia.Desktop" Version="11.3.8" />
    <!--Condition below is needed to remove Avalonia.Diagnostics package from build output in Release configuration.-->
    <PackageReference Condition="'$(Configuration)' == 'Debug'" Include="Avalonia.Diagnostics" Version="$(AvaloniaVersion)"/>
    <PackageReference Include="Material.Avalonia" Version="3.13.3-nightly.0.2" />
    <PackageReference Include="Material.Avalonia.DataGrid" Version="3.13.3-nightly.0.2" />
    <PackageReference Include="Material.Icons.Avalonia" Version="3.0.0-preview3.1" />
</ItemGroup>

<ItemGroup>
    <ProjectReference Include="..\InvoiceGeneratorDesktop_v2\InvoiceGeneratorDesktop_v2.csproj"/>
</ItemGroup>

Got it—here’s a cleaned-up exe project file that:

stays an executable (WinExe, UseAppHost=true)
publishes single-file, self-contained for Windows/macOS
sets Windows .ico + macOS bundle metadata
auto-builds a proper .app bundle after dotnet publish (macOS)

Replace the ProjectReference path with your library project path if needed.

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>net9.0</TargetFramework>
    <OutputType>WinExe</OutputType>
    <Nullable>enable</Nullable>
    <BuiltInComInteropSupport>true</BuiltInComInteropSupport>
    <Product>Invoice Generator</Product>
    <Company>Uncharted Limbo Collective</Company>

    <!-- Executable app host (required for single-file and macOS .app) -->
    <UseAppHost>true</UseAppHost>

    <!-- Single-file + self-contained by default (scoped per RID below if needed) -->
    <PublishSingleFile>true</PublishSingleFile>
    <SelfContained>true</SelfContained>

    <!-- Optional size/perf knobs -->
    <EnableCompressionInSingleFile>true</EnableCompressionInSingleFile>
    <IncludeNativeLibrariesForSelfExtract>false</IncludeNativeLibrariesForSelfExtract>
    <IncludeAllContentForSelfExtract>false</IncludeAllContentForSelfExtract>
    <!-- If trimming causes reflection issues, remove these two lines -->
    <!-- <PublishTrimmed>true</PublishTrimmed>
    <TrimMode>partial</TrimMode> -->

    <!-- Windows exe icon -->
    <ApplicationIcon>Assets/app.ico</ApplicationIcon>
  </PropertyGroup>

  <PropertyGroup>
    <ApplicationManifest>app.manifest</ApplicationManifest>
  </PropertyGroup>

  <!-- macOS bundle metadata -->
  <PropertyGroup>
    <CFBundleIdentifier>com.ulc.InvoiceGenerator</CFBundleIdentifier>
    <CFBundleName>Invoice Generator</CFBundleName>
    <CFBundleDisplayName>Invoice Generator</CFBundleDisplayName>
    <CFBundleShortVersionString>2.0.0</CFBundleShortVersionString>
    <CFBundleVersion>200</CFBundleVersion>
    <!-- Path to your .icns -->
    <MacIconPath>Assets/AppIcon.icns</MacIconPath>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Avalonia.Controls.DataGrid" Version="11.3.8" />
    <PackageReference Include="Avalonia.Desktop" Version="11.3.8" />
    <!-- Remove diagnostics in Release -->
    <PackageReference Condition="'$(Configuration)' == 'Debug'" Include="Avalonia.Diagnostics" Version="$(AvaloniaVersion)" />
    <PackageReference Include="Material.Avalonia" Version="3.13.3-nightly.0.2" />
    <PackageReference Include="Material.Avalonia.DataGrid" Version="3.13.3-nightly.0.2" />
    <PackageReference Include="Material.Icons.Avalonia" Version="3.0.0-preview3.1" />
  </ItemGroup>

  <ItemGroup>
    <!-- CHANGE this to your library project path -->
    <ProjectReference Include="..\YourLibrary\YourLibrary.csproj" />
  </ItemGroup>

  <!-- ===== macOS: build a .app bundle after publish ===== -->
  <Target Name="BundleMacApp"
          AfterTargets="Publish"
          Condition="'$(RuntimeIdentifier)' == 'osx-arm64' Or '$(RuntimeIdentifier)' == 'osx-x64'">
    <PropertyGroup>
      <AppName>$(AssemblyName)</AppName>
      <PublishOut>$(PublishDir)</PublishOut>
      <AppBundle>$(PublishOut)$(AppName).app</AppBundle>
      <MacOSDir>$(AppBundle)/Contents/MacOS</MacOSDir>
      <ResDir>$(AppBundle)/Contents/Resources</ResDir>
      <Plist>$(AppBundle)/Contents/Info.plist</Plist>
      <Launcher>$(PublishOut)$(AssemblyName)</Launcher> <!-- native host -->
    </PropertyGroup>

    <!-- Create bundle folders -->
    <Exec Command="bash -c 'set -e
      rm -rf &quot;$(AppBundle)&quot;;
      mkdir -p &quot;$(MacOSDir)&quot; &quot;$(ResDir)&quot;'" />

    <!-- Copy launcher and make it executable -->
    <Exec Command="bash -c 'set -e
      cp &quot;$(Launcher)&quot; &quot;$(MacOSDir)/$(AppName)&quot;;
      chmod +x &quot;$(MacOSDir)/$(AppName)&quot;'" />

    <!-- Copy icon if present -->
    <Exec Condition="Exists('$(ProjectDir)$(MacIconPath)')"
          Command="bash -c 'cp &quot;$(ProjectDir)$(MacIconPath)&quot; &quot;$(ResDir)/AppIcon.icns&quot;'" />

    <!-- Write Info.plist -->
    <Exec Command="bash -c 'cat &gt;&quot;$(Plist)&quot; &lt;&lt;PLIST
<?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?>
<!DOCTYPE plist PUBLIC &quot;-//Apple//DTD PLIST 1.0//EN&quot; &quot;http://www.apple.com/DTDs/PropertyList-1.0.dtd&quot;>
<plist version=&quot;1.0&quot;>
<dict>
  <key>CFBundleIdentifier</key><string>$(CFBundleIdentifier)</string>
  <key>CFBundleName</key><string>$(CFBundleName)</string>
  <key>CFBundleDisplayName</key><string>$(CFBundleDisplayName)</string>
  <key>CFBundleExecutable</key><string>$(AppName)</string>
  <key>CFBundlePackageType</key><string>APPL</string>
  <key>CFBundleShortVersionString</key><string>$(CFBundleShortVersionString)</string>
  <key>CFBundleVersion</key><string>$(CFBundleVersion)</string>
  <key>LSMinimumSystemVersion</key><string>11.0</string>
  <key>LSApplicationCategoryType</key><string>public.app-category.productivity</string>
  <key>NSHighResolutionCapable</key><true/>
  <key>NSPrincipalClass</key><string>NSApplication</string>
  <key>CFBundleIconFile</key><string>AppIcon</string>
</dict>
</plist>
PLIST'" />

    <!-- Optional: sign if SIGN_IDENTITY is provided -->
    <Exec Condition="'$(SIGN_IDENTITY)' != ''"
          Command='bash -c "codesign --force --deep --options runtime --sign &quot;$(SIGN_IDENTITY)&quot; &quot;$(AppBundle)&quot;"' />

    <!-- Optional: DMG if CREATE_DMG=true -->
    <Exec Condition="'$(CREATE_DMG)' == 'true'"
          Command='bash -c "hdiutil create -fs HFS+ -srcfolder &quot;$(AppBundle)&quot; -volname &quot;$(AppName)&quot; &quot;$(PublishOut)$(AppName).dmg&quot;"' />
  </Target>
</Project>

How you’ll use it

macOS .app:

dotnet publish -c Release -r osx-arm64
# => bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.app

Windows single-file:

dotnet publish -c Release -r win-x64
# => single .exe in publish/

If trimming causes runtime issues, remove the trimming lines (already commented).

That XML error is because the .csproj ended up with a raw < somewhere (likely the heredoc block for the Info.plist). XML attributes can’t contain unescaped <. Easiest fix: don’t embed a heredoc—write the plist with MSBuild’s WriteLinesToFile. Here’s a safe version of the mac bundling target you can drop into your exe project file (replaces the previous BundleMacApp target):

<!-- Build a .app after publish without any raw '<' in attributes -->
<Target Name="BundleMacApp"
        AfterTargets="Publish"
        Condition="'$(RuntimeIdentifier)' == 'osx-arm64' Or '$(RuntimeIdentifier)' == 'osx-x64'">

  <PropertyGroup>
    <AppName>$(AssemblyName)</AppName>
    <PublishOut>$(PublishDir)</PublishOut>
    <AppBundle>$(PublishOut)$(AppName).app</AppBundle>
    <MacOSDir>$(AppBundle)/Contents/MacOS</MacOSDir>
    <ResDir>$(AppBundle)/Contents/Resources</ResDir>
    <Plist>$(AppBundle)/Contents/Info.plist</Plist>
    <Launcher>$(PublishOut)$(AssemblyName)</Launcher>
  </PropertyGroup>

  <!-- Create bundle folders -->
  <Exec Command="bash -c 'set -e; rm -rf &quot;$(AppBundle)&quot;; mkdir -p &quot;$(MacOSDir)&quot; &quot;$(ResDir)&quot;'" />

  <!-- Copy native app host and make it executable -->
  <Exec Command="bash -c 'set -e; cp &quot;$(Launcher)&quot; &quot;$(MacOSDir)/$(AppName)&quot;; chmod +x &quot;$(MacOSDir)/$(AppName)&quot;'" />

  <!-- Copy icon if present -->
  <Exec Condition="Exists('$(ProjectDir)$(MacIconPath)')"
        Command="bash -c 'cp &quot;$(ProjectDir)$(MacIconPath)&quot; &quot;$(ResDir)/AppIcon.icns&quot;'" />

  <!-- Write Info.plist safely (no heredoc) -->
  <ItemGroup>
    <_PlistLines Include='&lt;?xml version="1.0" encoding="UTF-8"?&gt;' />
    <_PlistLines Include='&lt;!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"&gt;' />
    <_PlistLines Include='&lt;plist version="1.0"&gt;' />
    <_PlistLines Include='&lt;dict&gt;' />
    <_PlistLines Include='  &lt;key&gt;CFBundleIdentifier&lt;/key&gt;&lt;string&gt;$(CFBundleIdentifier)&lt;/string&gt;' />
    <_PlistLines Include='  &lt;key&gt;CFBundleName&lt;/key&gt;&lt;string&gt;$(CFBundleName)&lt;/string&gt;' />
    <_PlistLines Include='  &lt;key&gt;CFBundleDisplayName&lt;/key&gt;&lt;string&gt;$(CFBundleDisplayName)&lt;/string&gt;' />
    <_PlistLines Include='  &lt;key&gt;CFBundleExecutable&lt;/key&gt;&lt;string&gt;$(AppName)&lt;/string&gt;' />
    <_PlistLines Include='  &lt;key&gt;CFBundlePackageType&lt;/key&gt;&lt;string&gt;APPL&lt;/string&gt;' />
    <_PlistLines Include='  &lt;key&gt;CFBundleShortVersionString&lt;/key&gt;&lt;string&gt;$(CFBundleShortVersionString)&lt;/string&gt;' />
    <_PlistLines Include='  &lt;key&gt;CFBundleVersion&lt;/key&gt;&lt;string&gt;$(CFBundleVersion)&lt;/string&gt;' />
    <_PlistLines Include='  &lt;key&gt;LSMinimumSystemVersion&lt;/key&gt;&lt;string&gt;11.0&lt;/string&gt;' />
    <_PlistLines Include='  &lt;key&gt;LSApplicationCategoryType&lt;/key&gt;&lt;string&gt;public.app-category.productivity&lt;/string&gt;' />
    <_PlistLines Include='  &lt;key&gt;NSHighResolutionCapable&lt;/key&gt;&lt;true/&gt;' />
    <_PlistLines Include='  &lt;key&gt;NSPrincipalClass&lt;/key&gt;&lt;string&gt;NSApplication&lt;/string&gt;' />
    <_PlistLines Include='  &lt;key&gt;CFBundleIconFile&lt;/key&gt;&lt;string&gt;AppIcon&lt;/string&gt;' />
    <_PlistLines Include='&lt;/dict&gt;' />
    <_PlistLines Include='&lt;/plist&gt;' />
  </ItemGroup>

  <WriteLinesToFile File="$(Plist)" Lines="@(_PlistLines)" Overwrite="true" Encoding="UTF8" />

  <!-- Optional: sign if provided -->
  <Exec Condition="'$(SIGN_IDENTITY)' != ''"
        Command='bash -c "codesign --force --deep --options runtime --sign &quot;$(SIGN_IDENTITY)&quot; &quot;$(AppBundle)&quot;"' />

  <!-- Optional: DMG if requested -->
  <Exec Condition="'$(CREATE_DMG)' == 'true'"
        Command='bash -c "hdiutil create -fs HFS+ -srcfolder &quot;$(AppBundle)&quot; -volname &quot;$(AppName)&quot; &quot;$(PublishOut)$(AppName).dmg&quot;"' />
</Target>

Also confirm these properties exist once (top of the file)

<PropertyGroup>
  <TargetFramework>net9.0</TargetFramework>
  <OutputType>WinExe</OutputType>
  <UseAppHost>true</UseAppHost>
  <PublishSingleFile>true</PublishSingleFile>
  <SelfContained>true</SelfContained>

  <!-- Windows icon (ok to keep) -->
  <ApplicationIcon>Assets/app.ico</ApplicationIcon>

  <!-- macOS metadata + icon path -->
  <CFBundleIdentifier>com.ulc.InvoiceGenerator</CFBundleIdentifier>
  <CFBundleName>Invoice Generator</CFBundleName>
  <CFBundleDisplayName>Invoice Generator</CFBundleDisplayName>
  <CFBundleShortVersionString>2.0.0</CFBundleShortVersionString>
  <CFBundleVersion>200</CFBundleVersion>
  <MacIconPath>Assets/AppIcon.icns</MacIconPath>
</PropertyGroup>

Why the error happened

Your previous target used a heredoc (<<PLIST) inside an XML attribute. If any < slips through unescaped, MSBuild treats it as XML markup—hence:

'', hexadecimal value 0x3C, is an invalid attribute character

The WriteLinesToFile approach avoids that entirely.

Build it

# macOS .app
dotnet publish -c Release -r osx-arm64
# => bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.app

# Windows single-file
dotnet publish -c Release -r win-x64

If you still hit a line/column error, tell me which line 89 is now (paste 10 lines around it) and I’ll spot the stray character.

Ah—that’s just the encoding token. WriteLinesToFile wants "UTF-8" (with the hyphen), not "UTF8".

Replace this line:

<WriteLinesToFile File="$(Plist)" Lines="@(_PlistLines)" Overwrite="true" Encoding="UTF8" />

with:

<WriteLinesToFile File="$(Plist)" Lines="@(_PlistLines)" Overwrite="true" Encoding="UTF-8" />

That’s it. The valid values are things like UTF-8, Unicode, BigEndianUnicode, US-ASCII (hyphenated names). After the change:

dotnet publish -c Release -r osx-arm64
# => bin/Release/net9.0/osx-arm64/publish/YourApp.app

If you prefer, you can also omit the Encoding attribute entirely (it defaults to UTF-8).

Got it—let’s zero in on why the .app won’t open on macOS. The quickest way is to run the inner binary to see the real error, then apply the right fix.

1) Run it from Terminal (shows the real error)

cd bin/Release/net9.0/osx-arm64/publish
./InvoiceGeneratorDesktop_v2.app/Contents/MacOS/InvoiceGeneratorDesktop_v2

Tell me what it prints. Common messages map to fixes below.

2) Fast checks that fix a lot of silent failures

A) Quarantine (Gatekeeper) If Finder says nothing and it just bounces once, it’s often quarantine flags:

xattr -p com.apple.quarantine "InvoiceGeneratorDesktop_v2.app" 2>/dev/null || echo "no quarantine"
xattr -dr com.apple.quarantine "InvoiceGeneratorDesktop_v2.app"
open "InvoiceGeneratorDesktop_v2.app"

B) Architecture mismatch Make sure the app is arm64 if you published -r osx-arm64:

file InvoiceGeneratorDesktop_v2.app/Contents/MacOS/InvoiceGeneratorDesktop_v2
uname -m

If the binary says x86_64 but your Mac is arm64, republish with -r osx-arm64.
If you truly need Intel, install Rosetta: softwareupdate --install-rosetta.

C) Gatekeeper / codesign status Unsigned apps still run locally, but check anyway:

codesign -dv --verbose=4 InvoiceGeneratorDesktop_v2.app 2>&1 | head -n 20
spctl --assess --type execute -vv InvoiceGeneratorDesktop_v2.app || true

If you later want to distribute, sign & (optionally) notarize—but that’s separate.

3) Single-file + native libs (likely culprit on macOS)

Some native libraries (e.g., Avalonia’s) may need to be extracted when single-file is used on macOS. If the inner run shows errors like failing to load a .dylib, switch these two flags to true for macOS builds so native bits are self-extracted:

Add this to your exe project .csproj (keep your existing stuff; this only affects macOS RIDs):

<PropertyGroup Condition="'$(RuntimeIdentifier)' == 'osx-arm64' Or '$(RuntimeIdentifier)' == 'osx-x64'">
  <IncludeNativeLibrariesForSelfExtract>true</IncludeNativeLibrariesForSelfExtract>
  <IncludeAllContentForSelfExtract>true</IncludeAllContentForSelfExtract>
  <!-- If you still have trouble, temporarily disable single-file on macOS to test: -->
  <!-- <PublishSingleFile>false</PublishSingleFile> -->
</PropertyGroup>

Then republish:

dotnet publish -c Release -r osx-arm64
open InvoiceGeneratorDesktop_v2.app

4) Sanity test (rules out packaging issues)

If it still won’t launch, try a non-single-file macOS publish once:

dotnet publish -c Release -r osx-arm64 -p:PublishSingleFile=false
./bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2

If this works, the crash is specifically tied to single-file; keep the self-extract flags above, or ship non-single-file on macOS.

5) Other quick fixes

Executable bit (we set it in the target, but just in case):

chmod +x InvoiceGeneratorDesktop_v2.app/Contents/MacOS/InvoiceGeneratorDesktop_v2

Working dir assumptions: Avalonia assets should be embedded, but if you do File.Open("relative"), use absolute paths or AppContext.BaseDirectory.

If you can paste the console output from step 1 (running the inner binary), I’ll pinpoint the exact reason and give you a one-line fix.

Unhandled exception. System.TypeInitializationException: The type initializer for ‘SkiaSharp.SKImageInfo’ threw an exception. ---> System.DllNotFoundException: Unable to load shared library ‘libSkiaSharp’ or one of its dependencies. In order to help diagnose loading problems, consider setting the DYLD_PRINT_LIBRARIES environment variable: dlopen(/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/libSkiaSharp.dylib, 0x0001): tried: ‘/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/libSkiaSharp.dylib’ (no such file), ‘/System/Volumes/Preboot/Cryptexes/OS/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/libSkiaSharp.dylib’ (no such file), ‘/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/libSkiaSharp.dylib’ (no such file) dlopen(libSkiaSharp.dylib, 0x0001): tried: ‘libSkiaSharp.dylib’ (no such file), ‘/System/Volumes/Preboot/Cryptexes/OSlibSkiaSharp.dylib’ (no such file), ‘/usr/lib/libSkiaSharp.dylib’ (no such file, not in dyld cache), ‘libSkiaSharp.dylib’ (no such file) dlopen(/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/liblibSkiaSharp.dylib, 0x0001): tried: ‘/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/liblibSkiaSharp.dylib’ (no such file), ‘/System/Volumes/Preboot/Cryptexes/OS/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/liblibSkiaSharp.dylib’ (no such file), ‘/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/liblibSkiaSharp.dylib’ (no such file) dlopen(liblibSkiaSharp.dylib, 0x0001): tried: ‘liblibSkiaSharp.dylib’ (no such file), ‘/System/Volumes/Preboot/Cryptexes/OSliblibSkiaSharp.dylib’ (no such file), ‘/usr/lib/liblibSkiaSharp.dylib’ (no such file, not in dyld cache), ‘liblibSkiaSharp.dylib’ (no such file) dlopen(/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/libSkiaSharp, 0x0001): tried: ‘/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/libSkiaSharp’ (no such file), ‘/System/Volumes/Preboot/Cryptexes/OS/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/libSkiaSharp’ (no such file), ‘/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/libSkiaSharp’ (no such file) dlopen(libSkiaSharp, 0x0001): tried: ‘libSkiaSharp’ (no such file), ‘/System/Volumes/Preboot/Cryptexes/OSlibSkiaSharp’ (no such file), ‘/usr/lib/libSkiaSharp’ (no such file, not in dyld cache), ‘libSkiaSharp’ (no such file) dlopen(/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/liblibSkiaSharp, 0x0001): tried: ‘/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/liblibSkiaSharp’ (no such file), ‘/System/Volumes/Preboot/Cryptexes/OS/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/liblibSkiaSharp’ (no such file), ‘/Users/georgeadamon/Documents/Github/ULC/automation/Apps/InvoiceGeneratorDesktop_v2/InvoiceGeneratorDesktop_v2.Desktop/bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/liblibSkiaSharp’ (no such file) dlopen(liblibSkiaSharp, 0x0001): tried: ‘liblibSkiaSharp’ (no such file), ‘/System/Volumes/Preboot/Cryptexes/OSliblibSkiaSharp’ (no such file), ‘/usr/lib/liblibSkiaSharp’ (no such file, not in dyld cache), ‘liblibSkiaSharp’ (no such file)

at SkiaSharp.SkiaApi.sk_colortype_get_default_8888() at SkiaSharp.SkiaApi.sk_colortype_get_default_8888() at SkiaSharp.SKImageInfo..cctor() --- End of inner exception stack trace --- at Avalonia.Skia.PlatformRenderInterface..ctor(Nullable1 maxResourceBytes) at Avalonia.Skia.SkiaPlatform.Initialize(SkiaOptions options) at Avalonia.SkiaApplicationExtensions.<>c.<UseSkia>b__0_0() at Avalonia.AppBuilder.SetupUnsafe() at Avalonia.AppBuilder.Setup() at Avalonia.AppBuilder.SetupWithLifetime(IApplicationLifetime lifetime) at Avalonia.ClassicDesktopStyleApplicationLifetimeExtensions.StartWithClassicDesktopLifetime(AppBuilder builder, String[] args, Action1 lifetimeBuilder) at InvoiceGeneratorDesktop_v2.Desktop.Program.Main(String[] args)

Great—this is the classic macOS + single-file + Skia combo.

What’s happening: in single-file mode the native Skia libs (libSkiaSharp.dylib, libHarfBuzzSharp.dylib) are inside the bundle. On macOS they often need to be self-extracted at runtime. Right now they aren’t, so the loader can’t find libSkiaSharp.

Do these two fixes:

1) Make single-file builds self-extract on macOS

Add this to your exe project .csproj (keep your existing stuff):

<!-- Ensure native dylibs are extracted on macOS single-file -->
<PropertyGroup Condition="'$(RuntimeIdentifier)' == 'osx-arm64' Or '$(RuntimeIdentifier)' == 'osx-x64'">
  <IncludeNativeLibrariesForSelfExtract>true</IncludeNativeLibrariesForSelfExtract>
  <IncludeAllContentForSelfExtract>true</IncludeAllContentForSelfExtract>
</PropertyGroup>

(You previously had these set to false. They need to be true on macOS.)

2) Ensure the macOS native Skia bits are present

Add the macOS native assets package to the exe project (versions should match your Skia/Avalonia line; 2.88.x is typical for Avalonia 11.x):

<ItemGroup>
  <PackageReference Include="SkiaSharp.NativeAssets.Macos" Version="2.88.8" />
  <!-- (Optional, but recommended) -->
  <PackageReference Include="HarfBuzzSharp.NativeAssets.Macos" Version="2.8.2.3" />
</ItemGroup>

You don’t need to add SkiaSharp itself (Avalonia brings it), but adding the NativeAssets.Macos ensures the .dylibs are in the publish and thus self-extracted correctly.

Rebuild & test

dotnet clean
dotnet restore
dotnet publish -c Release -r osx-arm64
# run from Terminal to see any messages
./bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/InvoiceGeneratorDesktop_v2.Desktop

If it still fails:

Quick sanity check (no single-file):

dotnet publish -c Release -r osx-arm64 -p:PublishSingleFile=false
./bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop

If this works, the issue is purely single-file—keep the self-extract flags on for macOS.

Quarantine flag (Gatekeeper)

xattr -dr com.apple.quarantine "bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app"

Verify libs landed after extraction At first launch, .NET extracts to ~/Library/Application Support/.net/<YourApp>/.... If you want to control the location for debugging:
Terminal window
```
DOTNET_BUNDLE_EXTRACT_BASE_DIR="$(pwd)/.extract" \
./InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/InvoiceGeneratorDesktop_v2.Desktop
```
Then check .extract for libSkiaSharp.dylib / libHarfBuzzSharp.dylib.

Want me to pin exact package versions to your Avalonia version? Tell me your Avalonia.* and (if present) SkiaSharp versions from obj/project.assets.json or post your PackageReferences and I’ll line them up.

Unhandled exception. System.TypeInitializationException: The type initializer for ‘SkiaSharp.SKFontManager’ threw an exception. ---> System.TypeInitializationException: The type initializer for ‘SkiaSharp.SKObject’ threw an exception. ---> System.InvalidOperationException: The version of the native libSkiaSharp library (88.0) is incompatible with this version of SkiaSharp. Supported versions of the native libSkiaSharp library are in the range [88.1, 89.0). at SkiaSharp.SkiaSharpVersion.CheckNativeLibraryCompatible(Version minSupported, Version current, Boolean throwIfIncompatible) at SkiaSharp.SkiaSharpVersion.CheckNativeLibraryCompatible(Boolean throwIfIncompatible) at SkiaSharp.SKObject..cctor() --- End of inner exception stack trace --- at SkiaSharp.SKObject..ctor(IntPtr handle, Boolean owns) at SkiaSharp.SKFontManager..ctor(IntPtr handle, Boolean owns) at SkiaSharp.SKFontManager.SKFontManagerStatic..ctor(IntPtr x) at SkiaSharp.SKFontManager..cctor() --- End of inner exception stack trace --- at SkiaSharp.SKFontManager.get_Default() at Avalonia.Skia.FontManagerImpl..ctor() at Avalonia.Skia.SkiaPlatform.Initialize(SkiaOptions options) at Avalonia.SkiaApplicationExtensions.<>c.b__0_0() at Avalonia.AppBuilder.SetupUnsafe() at Avalonia.AppBuilder.Setup() at Avalonia.AppBuilder.SetupWithLifetime(IApplicationLifetime lifetime) at Avalonia.ClassicDesktopStyleApplicationLifetimeExtensions.StartWithClassicDesktopLifetime(AppBuilder builder, String[] args, Action`1 lifetimeBuilder) at InvoiceGeneratorDesktop_v2.Desktop.Program.Main(String[] args) zsh: abort

You’ve got a SkiaSharp version mismatch: the native dylib is 88.0, but your managed SkiaSharp expects [88.1, 89.0). Fix by pinning all Skia-related packages to the same compatible version and republishing so the right native dylibs get extracted.

1) Pin matching versions in your exe project

Add (or update) these PackageReferences so they align (these work well with Avalonia 11.3.x):

<ItemGroup>
  <!-- Make the managed & native versions match -->
  <PackageReference Include="SkiaSharp" Version="2.88.8" />
  <PackageReference Include="SkiaSharp.NativeAssets.Macos" Version="2.88.8" />

  <!-- HarfBuzz is used for text shaping; keep native in sync with its managed -->
  <PackageReference Include="HarfBuzzSharp" Version="2.8.2.3" />
  <PackageReference Include="HarfBuzzSharp.NativeAssets.MacOS" Version="2.8.2.3" />
</ItemGroup>

(If you already reference Skia/HarfBuzz indirectly via Avalonia, these entries will override to the specified versions, which is what we want.)

2) Keep self-extraction on for macOS single-file

(make sure this block is present)

<PropertyGroup Condition="'$(RuntimeIdentifier)' == 'osx-arm64' Or '$(RuntimeIdentifier)' == 'osx-x64'">
  <IncludeNativeLibrariesForSelfExtract>true</IncludeNativeLibrariesForSelfExtract>
  <IncludeAllContentForSelfExtract>true</IncludeAllContentForSelfExtract>
</PropertyGroup>

3) Clear caches so the old 88.0 dylib can’t sneak back

# from the exe project folder
rm -rf bin obj
dotnet nuget locals all --clear

# also clear the .NET single-file extraction cache for your app
rm -rf ~/Library/Application\ Support/.net/InvoiceGeneratorDesktop_v2.Desktop
# (adjust to your actual AssemblyName if different)

4) Re-publish and run

dotnet restore
dotnet publish -c Release -r osx-arm64
./bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/InvoiceGeneratorDesktop_v2.Desktop

If you still see a Skia mismatch

Print what dylib is loading:

export DYLD_PRINT_LIBRARIES=1
./bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop.app/Contents/MacOS/InvoiceGeneratorDesktop_v2.Desktop

If it’s pulling a stray libSkiaSharp.dylib from somewhere else, remove/rename that copy or adjust your path.

As a sanity check, try without single-file once (to isolate single-file issues):

dotnet publish -c Release -r osx-arm64 -p:PublishSingleFile=false
./bin/Release/net9.0/osx-arm64/publish/InvoiceGeneratorDesktop_v2.Desktop

Ping me with your current PackageReference list if you want me to lock exact versions to your Avalonia build.

To make that Notion link open directly in the desktop app instead of the browser, replace the https://www.notion.so/ prefix with the Notion app URI scheme:

notion://www.notion.so/uncharted-limbo/1076716ca1e880d1a502c5b9048ec857?v=a18414c6efeb4bad9e43552fb939e23e&source=copy_link

✅ Desktop-app version:

notion://www.notion.so/uncharted-limbo/1076716ca1e880d1a502c5b9048ec857?v=a18414c6efeb4bad9e43552fb939e23e&source=copy_link

You can click or paste that into Spotlight (⌘ + Space → paste → Enter) or use it anywhere hyperlinks are supported — it will open directly in the Notion desktop client instead of your browser (as long as Notion is installed).

i want to make this button align all the way to the right, and have the “exit to top right” icon that indicates opening in anew app

            <Expander IsExpanded="False">
                <Expander.Header>
                    <StackPanel Orientation="Horizontal">
                        <TextBlock
                            FontSize="14"
                            FontWeight="Bold"
                            Text="Company Details" />

                        <Button Click="Button_OnClick_Notion"></Button>
                    </StackPanel>


                </Expander.Header>

Here’s a clean way to push the button all the way right and show the “open in new app” icon (Material “OpenInNew”).

Add the Material Icons namespace to your XAML root (once per file):

xmlns:mi="clr-namespace:Material.Icons.Avalonia;assembly=Material.Icons.Avalonia"

Then use a Grid with two columns so the button hugs the right edge:

<Expander IsExpanded="False">
  <Expander.Header>
    <Grid ColumnDefinitions="*,Auto" VerticalAlignment="Center">
      <TextBlock
        Grid.Column="0"
        FontSize="14"
        FontWeight="Bold"
        Text="Company Details" />

      <Button
        Grid.Column="1"
        Click="Button_OnClick_Notion"
        ToolTip.Tip="Open in Notion"
        Background="Transparent"
        BorderBrush="Transparent"
        Padding="6"
        HorizontalAlignment="Right">
        <StackPanel Orientation="Horizontal" Spacing="6">
          <TextBlock Text="Open" />
          <mi:MaterialIcon Kind="OpenInNew" Width="16" Height="16"/>
        </StackPanel>
      </Button>
    </Grid>
  </Expander.Header>
</Expander>

Notes:

ColumnDefinitions="*,Auto" makes the text take all available space and the button auto-size, so it pins to the right.
If you want just the icon (no text), remove the <TextBlock Text="Open" />.
You already have Material.Icons.Avalonia in your project—this uses that (Kind="OpenInNew"). If the icon doesn’t show, double-check the namespace and package reference.

Got you — the icon control is there, but it’s not rendering because of a package/namespace mismatch. You’re on a preview of Material.Icons.Avalonia (3.0.0-preview3.1), which doesn’t line up with the usual API. Easiest fix: pin the stable package and use the correct namespace.

1) Pin the icon package to a stable version

In your exe project .csproj (the UI project), add/update:

<ItemGroup>
  <PackageReference Include="Material.Icons.Avalonia" Version="2.1.9" />
</ItemGroup>

Then dotnet restore.

2) Use the right namespace + control

At the top of your XAML file (where the Expander lives):

xmlns:materialIcons="clr-namespace:Material.Icons.Avalonia;assembly=Material.Icons.Avalonia"

Then update the header layout. Use a Grid so the button hugs the right edge, and the MaterialIcon shows:

<Expander IsExpanded="False">
  <Expander.Header>
    <Grid ColumnDefinitions="*,Auto" VerticalAlignment="Center">
      <TextBlock Grid.Column="0"
                 FontSize="14"
                 FontWeight="Bold"
                 Text="Company Details" />

      <Button Grid.Column="1"
              Click="Button_OnClick_Notion"
              ToolTip.Tip="Open in Notion"
              Background="Transparent"
              BorderBrush="Transparent"
              Padding="4"
              HorizontalAlignment="Right">
        <StackPanel Orientation="Horizontal" Spacing="6">
          <TextBlock Text="Open" />
          <materialIcons:MaterialIcon Kind="OpenInNew" Width="16" Height="16"/>
        </StackPanel>
      </Button>
    </Grid>
  </Expander.Header>
</Expander>

If it still doesn’t show

Make sure you have no other xmlns:mi=... pointing to a different assembly.
Try forcing a color (just to confirm it’s there):
<materialIcons:MaterialIcon Kind="OpenInNew" Width="16" Height="16" Foreground="CurrentColor"/>
Try the markup extension variant (same package):
<Button Content="{materialIcons:MaterialIconExt Kind=OpenInNew}" />

If you prefer to stay on the preview package, tell me which exact preview it is and I’ll adjust the control/namespace for that version.

The icon control is fine — the missing piece is the styles/resources that ship with Material.Icons.Avalonia. Without merging that resource dictionary, the control doesn’t know which font to use, so it renders “nothing”.

Fix

Make sure you reference a stable version (works great with Avalonia 11):

<PackageReference Include="Material.Icons.Avalonia" Version="2.1.9" />

In your App.axaml, merge the icons theme once:

<Application xmlns="https://github.com/avaloniaui"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             x:Class="YourNamespace.App">
  <Application.Styles>
    <!-- your app theme(s) here -->
    <StyleInclude Source="avares://Material.Icons.Avalonia/DefaultTheme.axaml"/>
  </Application.Styles>
</Application>

Keep the control as you have it:

xmlns:materialIcons="clr-namespace:Material.Icons.Avalonia;assembly=Material.Icons.Avalonia"

<materialIcons:MaterialIcon Kind="OpenInNew" Width="16" Height="16"/>

That should make the icon appear.

If you prefer to stay on the 3.x preview

The resource file name changed in some previews. Try:

<StyleInclude Source="avares://Material.Icons.Avalonia/Styles.axaml"/>

(Keep only one of the two StyleIncludes depending on your package version.)

Quick sanity checks

If it’s still blank, force a color/size:
<materialIcons:MaterialIcon Kind="OpenInNew" Width="18" Height="18" Foreground="Black"/>
Ensure there isn’t another xmlns:materialIcons pointing to a different assembly.
Rebuild/clean after changing packages: dotnet clean && dotnet restore && dotnet build.

Want me to look at your current App.axaml and package list? Paste them and I’ll adjust the exact StyleInclude for your version.

You’ve got two “theme” layers to play with in Material.Avalonia:

App theme/colors (Light/Dark + primary/secondary etc.)
Button variant (Filled / Outlined / Text / Elevated / Tonal) — i.e., how an individual button looks

Here’s how to set both.

1) App theme + colors (in `App.axaml`)

Add/adjust the Material theme once for your whole app:

<Application
    xmlns="https://github.com/avaloniaui"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:material="clr-namespace:Material.Styles;assembly=Material.Avalonia"
    x:Class="YourNamespace.App"
    RequestedThemeVariant="Light"> <!-- or Dark / Default -->

  <Application.Styles>
    <!-- Material default styles -->
    <StyleInclude Source="avares://Material.Avalonia/Styles/MaterialTheme.axaml" />

    <!-- Material 3 (You) color scheme -->
    <material:MaterialTheme
        BaseTheme="Light"             <!-- Light / Dark -->
        PrimaryColor="#6750A4"        <!-- brand color -->
        SecondaryColor="#625B71"
        TertiaryColor="#7D5260"
        ErrorColor="#B3261E"
        PrimaryContainer="#EADDFF" />
  </Application.Styles>
</Application>

(If a nightly uses different file names, keep your current Material includes and just add the <material:MaterialTheme …/> resource.)

2) Pick a button theme/variant per button

Material.Avalonia exposes variants via classes. Add one of these to your Button:

Filled – solid color button
Outlined – border, transparent background
Text – text-only
Elevated – raised (“card-like”) with shadow
Tonal (aka FilledTonal) – softer fill using secondary color

<!-- Filled button -->
<Button Classes="Filled" Content="Save" />

<!-- Outlined button -->
<Button Classes="Outlined" Content="Cancel" />

<!-- Text button -->
<Button Classes="Text" Content="Learn more" />

<!-- Elevated button -->
<Button Classes="Elevated" Content="Upload" />

<!-- Tonal (filled-tonal) button -->
<Button Classes="Tonal" Content="Open in Notion" />

Extras you might want

Icon + text:

<Button Classes="Outlined">
  <StackPanel Orientation="Horizontal" Spacing="8">
    <TextBlock Text="Open" />
    <materialIcons:MaterialIcon Kind="OpenInNew" Width="16" Height="16"/>
  </StackPanel>
</Button>

Full-width: HorizontalAlignment="Stretch"
Rounder corners: CornerRadius="12"
Compact height: Padding="8,6" (Material.Avalonia also has density styles you can apply app-wide if you prefer.)

If your classes don’t seem to take, tell me your exact Material.Avalonia version and I’ll map the right class names for that build (nightlies sometimes rename them).

Your button classes aren’t doing anything because (a) the Material styles aren’t merged, or (b) you’re on the 3.x nightly where the class names changed.

Here’s the quick fix for both cases—pick the block that matches your package version.

If you use a stable 2.x (`Material.Avalonia 2.1.x`)

Merge the Material styles in App.axaml:

<Application
  xmlns="https://github.com/avaloniaui"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:material="clr-namespace:Material.Styles;assembly=Material.Avalonia">
  <Application.Styles>
    <StyleInclude Source="avares://Material.Avalonia/Styles/MaterialTheme.axaml"/>
    <material:MaterialTheme BaseTheme="Light" PrimaryColor="#6750A4"/>
  </Application.Styles>
</Application>

Use the classic class names on the button:

<Button Classes="Filled"   Content="Save"/>
<Button Classes="Outlined" Content="Cancel"/>
<Button Classes="Text"     Content="Learn more"/>
<Button Classes="Elevated" Content="Upload"/>
<Button Classes="Tonal"    Content="Open in Notion"/>

If you use the 3.x nightly (you mentioned `3.13.3-nightly.0.2`)

Nightly builds renamed things. Use one of these two approaches:

A) New class names

<!-- App.axaml -->
<Application.Styles>
  <StyleInclude Source="avares://Material.Avalonia/Styles/MaterialTheme.axaml"/>
  <StyleInclude Source="avares://Material.Avalonia/Styles/Controls.axaml"/>
  <!-- optional theme colors -->
  <material:MaterialTheme BaseTheme="Light" PrimaryColor="#6750A4"/>
</Application.Styles>

<!-- Your view -->
<Button Classes="FilledButton"    Content="Save"/>
<Button Classes="OutlinedButton"  Content="Cancel"/>
<Button Classes="TextButton"      Content="Learn more"/>
<Button Classes="ElevatedButton"  Content="Upload"/>
<Button Classes="TonalButton"     Content="Open in Notion"/>

B) Attached property (also supported in 3.x)

xmlns:ma="clr-namespace:Material.Styles;assembly=Material.Avalonia"

<Button ma:ButtonAssist.Variant="Filled"   Content="Save"/>
<Button ma:ButtonAssist.Variant="Outlined" Content="Cancel"/>
<Button ma:ButtonAssist.Variant="Text"     Content="Learn more"/>
<Button ma:ButtonAssist.Variant="Elevated" Content="Upload"/>
<Button ma:ButtonAssist.Variant="Tonal"    Content="Open in Notion"/>

Troubleshooting checklist

Make sure App.axaml actually merges the Material styles (MaterialTheme.axaml and, for 3.x, Styles/Controls.axaml).
Ensure the namespace is correct:
- xmlns:material="clr-namespace:Material.Styles;assembly=Material.Avalonia"
- (for attached props) xmlns:ma="clr-namespace:Material.Styles;assembly=Material.Avalonia"
Clean + rebuild after switching versions: dotnet clean && dotnet restore && dotnet build.

If you tell me which Material.Avalonia version you’ve got right now, I’ll give you the exact one-liner to set the variant for that build.

although im building a page URL it doesnt open it

Console.WriteLine($"notion://www.notion.so/uncharted-limbo/{((MainViewModel)DataContext)?.SelectedClient.Name.Replace(" ","-")}-{((MainViewModel)DataContext)?.SelectedClient.Id}?source=copy_link\n");

    Process.Start(new ProcessStartInfo($"notion://www.notion.so/uncharted-limbo/{((MainViewModel)DataContext)?.SelectedClient.Name.Replace(" ","-")}-{((MainViewModel)DataContext)?.SelectedClient.Id}?source=copy_link\n") { UseShellExecute = true });

Two things are tripping this up:

you’ve got a newline at the end of the URL (\n)
on macOS you should launch URLs via open (Windows: UseShellExecute=true is fine)

Also: make the slug safe and URL-encode it.

using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Text.RegularExpressions;

void OpenNotionForSelectedClient()
{
    var vm = (MainViewModel)DataContext!;
    var name = vm?.SelectedClient?.Name ?? "";
    var id   = vm?.SelectedClient?.Id ?? "";

    // slugify the name like Notion does
    var slug = Regex.Replace(name.Trim().ToLowerInvariant(), @"[^a-z0-9]+", "-").Trim('-');

    var url = $"notion://www.notion.so/uncharted-limbo/{slug}-{id}?source=copy_link";
    // (no trailing newline!)

    if (OperatingSystem.IsMacOS())
    {
        // Use the macOS URL opener
        Process.Start(new ProcessStartInfo
        {
            FileName = "open",
            Arguments = url,
            UseShellExecute = false
        });
    }
    else if (OperatingSystem.IsWindows())
    {
        // Let the shell handle the custom URI scheme
        Process.Start(new ProcessStartInfo(url)
        {
            UseShellExecute = true
        });
    }
    else
    {
        // Linux desktop
        Process.Start("xdg-open", url);
    }
}

If it still doesn’t open on macOS, confirm the scheme is registered by running in Terminal:

open "notion://www.notion.so/test"

If that fails, install/repair the Notion desktop app.

you’re right—Notion keeps capitalization in the slug. just replace “bad” chars with hyphens without lowercasing.

here’s a drop-in that preserves caps, collapses repeats, trims edges, and still opens via the right launcher per OS:

using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Text.RegularExpressions;

void OpenNotionForSelectedClient()
{
    var vm = (MainViewModel)DataContext!;
    var name = vm?.SelectedClient?.Name?.Trim() ?? "Untitled";
    var id   = vm?.SelectedClient?.Id ?? "";

    // Preserve capitals; replace any non A–Z/a–z/0–9 with hyphens; collapse repeats; trim edges
    var slug = Regex.Replace(name, @"[^A-Za-z0-9]+", "-").Trim('-');
    var slugEscaped = Uri.EscapeDataString(slug); // keeps hyphens, encodes non-ASCII safely

    var url = $"notion://www.notion.so/uncharted-limbo/{slugEscaped}-{id}?source=copy_link";

    if (OperatingSystem.IsMacOS())
    {
        Process.Start(new ProcessStartInfo
        {
            FileName = "open",
            Arguments = url,
            UseShellExecute = false
        });
    }
    else if (OperatingSystem.IsWindows())
    {
        Process.Start(new ProcessStartInfo(url) { UseShellExecute = true });
    }
    else
    {
        Process.Start("xdg-open", url);
    }
}

if your titles can include non-latin characters and you want to keep them (Notion does), the EscapeDataString will make the URL safe while preserving capitals.

the ui doesnt refresh

private void Button_OnClick_RefreshClientInfo(object? sender, RoutedEventArgs e) { var dc = ((MainViewModel)DataContext); var id = dc?.SelectedClient?.Id ?? "";

    Console.WriteLine(id);
    dc?.LoadClientsAsync();

    foreach (var c in dc.FilteredClients)
    {
        if (c.Id != id) continue;

        dc.SelectClientCommand.Execute(c);
        Console.WriteLine("Selected");

        break;
    }
}

Your handler fires LoadClientsAsync() and then immediately loops the old list. You never await the reload, so the UI/VM hasn’t updated yet. Also make sure the collection/property change happens on the UI thread.

Try this pattern:

using Avalonia.Threading;
using System.Linq;

private async void Button_OnClick_RefreshClientInfo(object? sender, RoutedEventArgs e)
{
    if (DataContext is not MainViewModel dc) return;

    var id = dc.SelectedClient?.Id;

    // 1) Await the reload
    await dc.LoadClientsAsync();

    // 2) Re-select the same client (after list is refreshed)
    var found = dc.FilteredClients?.FirstOrDefault(c => c.Id == id);
    if (found is not null)
    {
        // either set the property...
        dc.SelectedClient = found;

        // ...or use your command if that's where selection logic lives:
        // if (dc.SelectClientCommand.CanExecute(found))
        //     dc.SelectClientCommand.Execute(found);
    }
}

Make sure your VM updates actually notify the UI

Inside LoadClientsAsync():

If you replace the collection:

Clients = new ObservableCollection<Client>(await _svc.GetClientsAsync());
OnPropertyChanged(nameof(Clients));                 // notify bindings
OnPropertyChanged(nameof(FilteredClients));         // if it's computed from Clients

If you mutate an ObservableCollection, do it on the UI thread:

var items = await _svc.GetClientsAsync();
await Dispatcher.UIThread.InvokeAsync(() =>
{
    Clients.Clear();
    foreach (var c in items) Clients.Add(c);
});

If FilteredClients is a LINQ property like Clients.Where(...), you must raise PropertyChanged for it after reloading, or switch to an ICollectionView and call Refresh().

Other common gotchas

Don’t use ConfigureAwait(false) in LoadClientsAsync() when updating properties; it may switch threads. If you must, marshal back with Dispatcher.UIThread.InvokeAsync(...).
If selection is bound in XAML (SelectedItem="{Binding SelectedClient, Mode=TwoWay}"), prefer setting SelectedClient instead of executing the command.
Ensure SelectedClient setter raises PropertyChanged.

If you want, paste LoadClientsAsync() and how FilteredClients/SelectedClient are defined, and I’ll tailor the exact notifications you need.