MAUI - Access to the path .dll is denied

[vsfeedback]

This issue has been moved from a ticket on Developer Community.

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I created new Maui project and I cannot work due to error.
After start debugging, stop, and try to run again.

System.UnauthorizedAccessException: Access to the path 'C:\Users\xxx\source\repos\MauiSygic\obj\Debug\net9.0-android\android\assets\arm64-v8a\Mauixxx.dll' is denied.
1>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.0-rc.1.80\tools\Xamarin.Android.Common.targets(1415,3): error XALNS7019:    at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
1>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.0-rc.1.80\tools\Xamarin.Android.Common.targets(1415,3): error XALNS7019:    at System.IO.File.InternalDelete(String path, Boolean checkHost)
1>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.0-rc.1.80\tools\Xamarin.Android.Common.targets(1415,3): error XALNS7019:    at Microsoft.Android.Build.Tasks.Files.CopyIfChanged(String source, String destination) in /Users/runner/work/1/s/xamarin-android/external/xamarin-android-tools/src/Microsoft.Android.Build.BaseTasks/Files.cs:line 125
1>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.0-rc.1.80\tools\Xamarin.Android.Common.targets(1415,3): error XALNS7019:    at Xamarin.Android.Tasks.MonoAndroidHelper.CopyAssemblyAndSymbols(String source, String destination) in /Users/runner/work/1/s/xamarin-android/src/Xamarin.Android.Build.Tasks/Utilities/MonoAndroidHelper.cs:line 344
1>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.0-rc.1.80\tools\Xamarin.Android.Common.targets(1415,3): error XALNS7019:    at Xamarin.Android.Tasks.LinkAssembliesNoShrink.CopyIfChanged(ITaskItem source, ITaskItem destination) in /Users/runner/work/1/s/xamarin-android/src/Xamarin.Android.Build.Tasks/Tasks/LinkAssembliesNoShrink.cs:line 161
1>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.0-rc.1.80\tools\Xamarin.Android.Common.targets(1415,3): error XALNS7019:    at Xamarin.Android.Tasks.LinkAssembliesNoShrink.RunTask() in /Users/runner/work/1/s/xamarin-android/src/Xamarin.Android.Build.Tasks/Tasks/LinkAssembliesNoShrink.cs:line 76
1>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.0-rc.1.80\tools\Xamarin.Android.Common.targets(1415,3): error XALNS7019:    at Microsoft.Android.Build.Tasks.AndroidTask.Execute() in /Users/runner/work/1/s/xamarin-android/external/xamarin-android-tools/src/Microsoft.Android.Build.BaseTasks/AndroidTask.cs:line 25

I using in project global.json:

{
  "sdk": {
    "version": "9.0.100-rc.1.24452.12",
    "rollForward": "latestPatch"
  }
}

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Original Comments

Feedback Bot on 10/4/2024, 01:14 AM:

We have directed your feedback to the appropriate engineering team for further evaluation. The team will review the feedback and notify you about the next steps.

Samantha Houts [MSFT] on 10/14/2024, 00:46 PM:

Sometimes we see this when the path is too long. If you move your project to a shorter path, does it build? Does this happen with every project or just this one? Does it happen every build? Thanks!

Why do we ask for more info?
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Kopernik Mikolaj on 10/18/2024, 00:44 AM:

(private comment, text removed)

[samhouts]

@dellis1972 maybe another thing to be resolved by #9423?

[dellis1972]

Possibly yes :D

[dellis1972]

More likely resolved by dotnet/android-tools#245 and #9423

[jonpryor]

Please try again with .NET 9 GA. The various fixes to try to improve this scenario (be53aed, others) are only in .NET 9 GA.

[eerojaaskelainen]

Issue seems to exist in latest .NET 9 version also. If it matters, mine is a multi-project app (migrated from Xamarin.Forms).

Versions:

• Visual Studio: 17.12.3
• .NET: 9.0.101
• MAUI: 9.0.10

Initial builds work OK, but rebuild fails.

Build output:

2>Done building project "MyApp.Droid.csproj".
2>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.7\tools\Xamarin.Android.Common.targets(1420,3): error XALNS7019: System.UnauthorizedAccessException: Access to the path 'C:\Temp\MyApp\obj\Debug\net9.0-android\android\assets\x86_64\MyApp.Droid.dll' is denied.
2>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.7\tools\Xamarin.Android.Common.targets(1420,3): error XALNS7019:    at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
2>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.7\tools\Xamarin.Android.Common.targets(1420,3): error XALNS7019:    at System.IO.File.InternalDelete(String path, Boolean checkHost)
2>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.7\tools\Xamarin.Android.Common.targets(1420,3): error XALNS7019:    at Microsoft.Android.Build.Tasks.Files.CopyIfChangedOnce(String source, String destination) in /Users/runner/work/1/s/xamarin-android/external/xamarin-android-tools/src/Microsoft.Android.Build.BaseTasks/Files.cs:line 197
2>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.7\tools\Xamarin.Android.Common.targets(1420,3): error XALNS7019:    at Microsoft.Android.Build.Tasks.Files.CopyIfChanged(String source, String destination) in /Users/runner/work/1/s/xamarin-android/external/xamarin-android-tools/src/Microsoft.Android.Build.BaseTasks/Files.cs:line 176
2>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.7\tools\Xamarin.Android.Common.targets(1420,3): error XALNS7019:    at Xamarin.Android.Tasks.MonoAndroidHelper.CopyAssemblyAndSymbols(String source, String destination) in /Users/runner/work/1/s/xamarin-android/src/Xamarin.Android.Build.Tasks/Utilities/MonoAndroidHelper.cs:line 394
2>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.7\tools\Xamarin.Android.Common.targets(1420,3): error XALNS7019:    at Xamarin.Android.Tasks.LinkAssembliesNoShrink.CopyIfChanged(ITaskItem source, ITaskItem destination) in /Users/runner/work/1/s/xamarin-android/src/Xamarin.Android.Build.Tasks/Tasks/LinkAssembliesNoShrink.cs:line 161
2>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.7\tools\Xamarin.Android.Common.targets(1420,3): error XALNS7019:    at Xamarin.Android.Tasks.LinkAssembliesNoShrink.RunTask() in /Users/runner/work/1/s/xamarin-android/src/Xamarin.Android.Build.Tasks/Tasks/LinkAssembliesNoShrink.cs:line 76
2>C:\Program Files\dotnet\packs\Microsoft.Android.Sdk.Windows\35.0.7\tools\Xamarin.Android.Common.targets(1420,3): error XALNS7019:    at Microsoft.Android.Build.Tasks.AndroidTask.Execute() in /Users/runner/work/1/s/xamarin-android/external/xamarin-android-tools/src/Microsoft.Android.Build.BaseTasks/AndroidTask.cs:line 25

Edit:
Upon further investigation, it seems that msbuild.exe ("C:\Program Files\Microsoft Visual Studio\2022\Professional\MSBuild\Current\Bin\amd64\MSBuild.exe" /nologo /nodemode:1 /nodeReuse:true /low:false) is locking the file. After killing that process, rebuild works.

[FM1973]

I got the same problem and it is really annoying.
I currently use "taskkill /IM "msbuild.exe" /F" but this is just a workaround...

[rogue-pogue]

Same problem

[tranb3r]

Same problem.
@jonpryor Why is this issue closed? Has it been fixed? In which release?

[dellis1972]

There were a couple of fixes in this area. The commit be53aed might well have been related. And GitHub Auto closed this Issue when that PR was merged.

That said is it more accurate that PR #9531 fixes this issue. This has been cherry-picked to the .net 9 release branch via 974a5ab. I'm not sure when that is being released though. @jonpryor any ideas when that commit will actually make it into a release?

If anyone is seeing this on the 17.12.3 please get us binlogs of the issue (with the error in it) as it will give us some pointers as to what is going on .

That said We should move the conversation over to #9133 which I will re-open as it has more up to date information,

[uholeschak]

At least I have this issue also in 17.12.3. This is absolutely nerving. You always have to delete the obj dir before the every build.