WinUI 3 release mode crash Microsoft.ui.xaml.dll,

[jpcassano]

Describe the bug

When trying to launch a packaged WinUI 3 application in Release mode that was created using the Blank App, Packaged (WinUI 3 in Desktop) project template, I receive an exception stating, "Faulting module name: Microsoft.ui.xaml.dll, version: 3.1.5.0" and the application crashes.

Steps to reproduce the bug

1. Launch Microsoft Visual Studio Professional 2022 (64-bit) - Version 17.11.1 on Windows 11 Pro Version 23H2 Build 22631.4037.
2. Select Create a new project and use the Blank App, Packaged (WinUI 3 in Desktop) project template to create a new project.
3. Add the <WindowsAppSDKSelfContained>true</WindowsAppSDKSelfContained> parameter to the application .csproj file to indicate that the application should be self contained.
4. Select release and x64 from the configuration manager and try to run the application.
5. The application crashes

Expected behavior

The application should launch without an exception.

Screenshots

NuGet package version

WinUI 3 - Windows App SDK 1.5.6: 1.5.240802000

Windows version

Windows 11 (22H2): Build 22621

Additional context

The application also crashes after successfully installing if you use the create app package option by right clicking the project file and following the steps to sideload the app. The msix is created and installs the app but the application will crash when launching and the event viewer shows "Faulting module name: Microsoft.ui.xaml.dll, version: 3.1.5.0",

[github-actions]

Hi I'm an AI powered bot that finds similar issues based off the issue title.

Please view the issues below to see if they solve your problem, and if the issue describes your problem please consider closing this one. Thank you!

Closed similar issues:

• WinUI 3 - Blank App, Packaged (WinUI 3 in Desktop) C# project template crashes in Release configuration (#9675), similarity score: 0.85
• WinUI3 unmodified template crashes in release config: Unhandled exception at 0x00007FFBA70552F5 (Microsoft.ui.xaml.dll): 0xC000027B: An application-internal exception has occurred (parameters: 0x000001D814FC4330, 0x0000000000000002). (#9793), similarity score: 0.84
• WinUI 3.0 in Desktop crash on startup (#2773), similarity score: 0.82

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[jpcassano]

As described in the comments of the linked issues this is a bug that will be fixed in Windows App SDK 1.6. The workaround for this issue is to set <PublishTrimmed>false</PublishTrimmed> in the pubxml files for release builds.

[Cyp9715]

<PropertyGroup>
  <PublishTrimmed Condition="'$(Configuration)' == 'Debug'">False</PublishTrimmed>
  <PublishTrimmed Condition="'$(Configuration)' != 'Debug'">False</PublishTrimmed>
</PropertyGroup>

Modifying the .pubxml file as shown above resolved the issue.
However, why has Microsoft set this as the default option to True?
Honestly, I'm not entirely sure what this feature does, but if there is a potential issue, it would be better to set False as the default option to ensure proper functionality.