AVLN2002 Duplicate x:Class directive, (My App).App is already used in /App.axaml

[JAAYapps]

Describe the bug

I'm having an issue with the axaml files for some reason. Everything in the file is correct in my App.axaml but it's giving me this AVLN2002 Duplicate x:Class directive, {My app name here}.App is already used in /App.axaml

I'm not sure what is going on and I looked everywhere for a solution online. I can compile the app on Linux just fine, but not Windows 10 or 11. I'm not sure what is happening because I made another test project and it works on Windows and Linux.

To Reproduce

Unsure how to reproduce due to difficulties trying to create issue on other Avalonia projects.

Expected behavior

Should just compile without issue on Windows and Linux.

Avalonia version

11.2.0

OS

Windows

Additional context

I can't reproduce the issue on new projects. Sorry if it's not clear. I tried downgrading the Avalonia version, and changing the x:Class to an invalid namespace (Didn't give a different error, but uses the invalid namespace name in the same error).

[maxkatz6]

There likely is some misconfiguration in your old project. Can't tell what's exactly without project itself.
Could be duplicated registrations in csproj file.

[jurihock]

Hi! I had exactly the same build error. In my case, however, this happened because I accidentally backed up the project into the project folder itself. As a result, the project files were effectively duplicated.