[Bug]: Windows Sandbox failed to initialize

[wangyk55]

Windows Sandbox version

0.5.3.0

Windows build number

10.0.26200.0

Other software

No response

Steps to reproduce the bug

1. Install Windows Sandbox from Windows Features in Control Panel.
2. Start Windows Sandbox.
3. A window about downloading and updating pops up.
4. An error window pops up, saying "Windows Sandbox failed to initialize. Exception of type 'System.Exception' was thrown." with no error code.

Expected result

Windows Sandbox is supposed to start.

Actual result

The "downloading and updating" window only pops up at the first time after installing Windows Sandbox. Then each time I start Windows Sandbox, the error window pops up immediately.

Included System Information

Edition Windows 11 Pro
Version 25H2
Installed on ‎7/‎18/‎2025
OS build 26200.8457
Experience Windows Feature Experience Pack 1000.26100.304.0