Regression: App Installer 1.27 or 1.28 crashes on Windows 10 due to Microsoft.UI.Xaml.dll (0xc000027b)

Relevant area(s)

WinGet CLI

Relevant command(s)

No response

Brief description of your issue

After the automatic update to App Installer version 1.27 or 1.28, the application fails to launch or crashes immediately when opening any package files. Reverting to version 1.26.510.0 resolves the issue completely, suggesting a regression in the new WinAppSDK-based architecture on Windows 10.

Log:

Faulting application name: AppInstaller.exe, version: 1.27.460.0, time stamp: 0x69695b8f
Faulting module name: Microsoft.UI.Xaml.dll, version: 3.1.8.0, time stamp: 0x74c53e9a
Exception code: 0xc000027b
Fault offset: 0x000000000039dec5
Faulting process id: 0x237c
Faulting application start time: 0x01dcad59a644d8c4
Faulting application path: C:\Program Files\WindowsApps\Microsoft.DesktopAppInstaller_1.27.460.0_x64__8wekyb3d8bbwe\AppInstaller.exe
Faulting module path: C:\Program Files\WindowsApps\Microsoft.WindowsAppRuntime.1.8_8000.770.947.0_x64__8wekyb3d8bbwe\Microsoft.UI.Xaml.dll
Report Id: 999c8c1d-ab23-4048-a8b1-de94b12d67ee
Faulting package full name: Microsoft.DesktopAppInstaller_1.27.460.0_x64__8wekyb3d8bbwe
Faulting package-relative application ID: App

It may be related to these issues in the past:
Issue-5889
Issue-5847
WindowsAppSDK-Issue-6254
WindowsAppSDK-Issue-6117

Steps to reproduce

1. Ensure Windows 10 Build 19045 is installed.
2. Update App Installer to version 1.27 or 1.28 (The version that uses the WindowsAppRuntime.1.8).
3. Double-click any package.
4. The application crashes without a visible UI, or a crash event is logged in Event Viewer.

Expected behavior

The App Installer UI should appear and allow the user to install or update the package.

Actual behavior

Application fails to launch or crashes.

Environment

Windows Package Manager: v1.12.460 or v1.28.190
Windows: Windows.Desktop v10.0.19045.6456
Package: Microsoft.DesktopAppInstaller v1.27.460.0 or v1.28.190.0

Reproduce the crash on Windows 10 build 19045 with App Installer 1.27 or 1.28, then compare the Event Viewer fault against the linked issues 5889, 5847, WindowsAppSDK 6254, and 6117. No source file or test is named; done means App Installer launches and opens package files without the Microsoft.UI.Xaml.dll crash.