Published unpackaged, Single File no longer launches in 1.8

[Higeneko9]

Describe the bug

I’ve recently updated my project from version 1.7.5 (1.7.251014001) to 1.8.2 (1.8.251003001) and noticed that the published single-file app no longer launched.

The following are repro projects:

PublishNotLaunch1.7.zip

PublishNotLaunch1.8.zip

I got the following message when I try to run the published single file:

PublishNotLaunch.exe: WinRT originate error - 0x80004005 : ‘Cannot locate resource from ‘ms-appx:///MainWindow.xaml’.’.

Therefore, I copied ‘MainWindow.xbf” file along with the published single file exe and confirmed the app launched.

It may same reason as this bug, which generated code points wrong resource path might cause this.

I could copy all XBF files to work around this issue, but it would be nice if other way to work around this issue yet still create a single exe file.

Thank you!

Why is this important?

This issue prevents the project from being updated to version 1.8.

Steps to reproduce the bug

1. Open PublishNotLaunch1.8.zip
2. Publish the project
3. Run published single exe file (PublishNotLaunch.exe)

Actual behavior

App doesn't launch

Expected behavior

App must launch

Screenshots

No response

NuGet package version

WinUI 3 - Windows App SDK 1.8.2: 1.8.251003001

Windows version

Windows 11 (24H2): Build 26100

Additional context

No response

[MitchRazga]

I ran into a similar problem where an unpackaged app would fail to run entirely.
The project compiled successfully and produced output files, but the app crashed immediately on startup, both with and without NativeAOT.

I was able to determine that
<EnableMsixTooling>true</EnableMsixTooling>
is always required even when
<WindowsPackageType>None</WindowsPackageType>

Without that, basically any xaml that had a InitializeComponent() call doesn't seem to embed correctly.

Your repro helped me identify that so thanks for uploading 😄