Running unpackaged Windows app as admin prevents FilePicker from working

[beeradmoore]

Description

Not sure why, but FilePicker throws an exception when trying to use it in an application running as admin. Unsure what else could be broken. Should test suite be re-run as admin as well as standard user?

Exception message is an empty string and the stacktrace only shows my code. Unsure if this is a result of debugging as admin, or if that is the exception that it threw.

Excpetion itself is of type System.Runtime.InteropServices.COMException.

Discovery story:
Created an installer with NSIS for distribting dev tool internally. After sending out first builds I was getting reports that tool does not work on first launch. My installer has a "launch now" at the end of the installer and because the installer runs as admin so does the launched process. Closing and re-opening my application works as expected.

Steps to Reproduce

From scratch:

1. Launch VS as standard user and create MAUI project
2. Convet to unpackged app (add <WindowsPackageType>None</WindowsPackageType> to csproj, and change launchSettings.json to use Project for commandName)
3. Add file picker code
4. See that the code works
5. Close VS
6. Launch VS as admin (the following steps can also be reproduced by launching a built exe as admin)
7. Try use file picker

From provided repro:

1. Launch VS as standard user and open FilePickerAsAdmin.sln
2. Debug the program and press the Browse for file button. This should present a picker and allows you to pick a file. It does nothing with this file, just displays an alert that you were able to pick a file.
3. Close VS
4. Launch VS as admin (the following steps can also be reproduced by launching a built exe as admin)
5. Try press the Browse for file button again
6. Error message with nothing helpful should be displayed.

Link to public reproduction project repository

https://github.com/beeradmoore/maui-issue-FilePickerAsAdmin

Version with bug

8.0.7 SR2

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

Unknown/Other

Affected platforms

Windows

Affected platform versions

Windows 11 23H2

Did you find any workaround?

No

Relevant log output

No response

[ghost]

We've added this issue to our backlog, and we will work to address it as time and resources allow. If you have any additional information or questions about this issue, please leave a comment. For additional info about issue management, please read our Triage Process.

[drasticactions]

This is a WinUI3 bug, microsoft/WindowsAppSDK#2504. The APIs invoked by MAUI in essentials are the same you would use when building a straight WinUI 3 app, and building a file picker there and running it as admin will cause the same exception. Fixing the linked bug should fix this issue. Sorry.

[beeradmoore]

I have a WinUI3 (non-MAUI) app that I've had users run as admin and not had a problem so I didn't even think of a WinUI3 issue. Turns out it's because open file dialog is only in un-released dev build that would have been an issue come next update. Tested it as admin and got the same result as above.

Thanks for the thread link, looks like there are some workarounds in there I'll dig into for both my MAUI and WinUI3 projects.