[Known Build Error] build fails: GetAssemblyAttributes IOException - Microsoft.DotNet.ApiCompat.Task.dll in use by another process

[kotlarmilos]

Build Information

Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1470577
Build error leg or test failing: Build AoT: macOS (arm64) — GetAssemblyAttributes task fails building Microsoft.DotNet.ApiCompat.Task
Pull request: #54713

Error Message

The AoT: macOS (arm64) build leg intermittently fails because the GetAssemblyAttributes task cannot open Microsoft.DotNet.ApiCompat.Task.dll — the file is locked by another concurrent process during the build:

/Users/runner/work/1/s/.dotnet/sdk/.../Microsoft.NET.Sdk.targets(1200,5): error MSB4018: The "GetAssemblyAttributes" task failed unexpectedly. [.../Microsoft.DotNet.ApiCompat.Task.csproj]
... error MSB4018: System.IO.IOException: The process cannot access the file '.../artifacts/obj/Microsoft.DotNet.ApiCompat.Task/Release/net10.0/Microsoft.DotNet.ApiCompat.Task.dll' because it is being used by another process.
   at Microsoft.NET.Build.Tasks.FileUtilities.GetAssemblyVersion(String sourcePath)
   at Microsoft.NET.Build.Tasks.GetAssemblyAttributes.ExecuteCore()

This is an intermittent build-infrastructure file-locking race, unrelated to the code under test.

{
  "ErrorMessage": "Microsoft.DotNet.ApiCompat.Task.dll' because it is being used by another process",
  "ErrorPattern": "",
  "BuildRetry": true,
  "ExcludeConsoleLog": true
}

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1470577
Error message validated: [Microsoft.DotNet.ApiCompat.Task.dll' because it is being used by another process]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 6/18/2026 2:57:59 PM UTC

Report

Build	Repository	Step Name	Console log	Pull Request
1490501	dotnet/sdk	🟣 Build	Log	#55110
3012397	dotnet-sdk	🟣 Build	Log
1488626	dotnet/sdk	🟣 Build	Log	#55031
3011875	dotnet-sdk	🟣 Build	Log
1487663	dotnet/sdk	🟣 Build	Log	#55069
3011532	dotnet-sdk	🟣 Build	Log
3011558	dotnet-sdk	🟣 Build	Log
3011508	dotnet-sdk	🟣 Build	Log
3011177	dotnet-sdk	🟣 Build	Log
1486691	dotnet/sdk	🟣 Build	Log
3011052	dotnet-sdk	🟣 Build	Log
3011002	dotnet-sdk	🟣 Build	Log
3010548	dotnet-sdk	🟣 Build	Log
3009822	dotnet-sdk	🟣 Build	Log
1484178	dotnet/sdk	🟣 Build	Log	#55040
3009128	dotnet-sdk	🟣 Build	Log
3009026	dotnet-sdk	🟣 Build	Log
1483356	dotnet/sdk	🟣 Build	Log
3008912	dotnet-sdk	🟣 Build	Log
1482796	dotnet/sdk	🟣 Build	Log	#54904
3008697	dotnet-sdk	🟣 Build	Log
3008329	dotnet-sdk	🟣 Build	Log
3006766	dotnet-sdk	Build Cache Updater	Log
3006534	dotnet-sdk	🟣 Build	Log
1477160	dotnet/sdk	🟣 Build	Log	#54938
3004809	dotnet-sdk	🟣 Build	Log
1470577	dotnet/sdk	🟣 Build	Log	#54713

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
1	22	27

[MichaelSimons]

@dotnet/area-infrastructure-libraries, @ViktorHofer - Can someone take a look at this re-occurring build error while building ApiCompat. Here is a direct link to a binlog of one occurrence. TIA.

[ViktorHofer]

Can I please ask you to use the dotnet-msbuild plugin and ask copilot to investigate the binlog? Our goal is to make binlog investigation completely autonomous.