GenerateBundle Task fails writing to singlefilehost.exe

[dsplaisted]

Build Information

Build: https://dev.azure.com/dnceng-public/cbb18261-c48f-4abb-8651-8cdcb5474649/_build/results?buildId=1146095
Build error leg or test failing: Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution
Pull request: #50648

Error Message

Fill the error message using step by step known issues guidance.

{
  "ErrorMessage": "",
  "ErrorPattern": "The process cannot access the file '.*singlefilehost\\.exe' because it is being used by another process",
  "BuildRetry": false,
  "ExcludeConsoleLog": false
}

Known issue validation

Build: 🔎 https://dev.azure.com/dnceng-public/public/_build/results?buildId=1146095
Error message validated: [The process cannot access the file '.*singlefilehost\.exe' because it is being used by another process]
Result validation: ✅ Known issue matched with the provided build.
Validation performed at: 9/12/2025 3:27:55 PM UTC

Report

Build	Definition	Test	Pull Request
1151858	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50901
1151984	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50874
1151881	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50906
1151912	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50907
1151867	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50867
1151384	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.5.WorkItemExecution	#50876
1151933	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50908
1151670	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50897
1151916	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50844
1151668	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50904
1151637	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50903
1151669	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution
1151662	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution
1151526	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50897
1151470	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50648
1151381	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.5.WorkItemExecution	#50867
1151234	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.5.WorkItemExecution	#50648
1151259	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.5.WorkItemExecution	#50894
1150440	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50780
1149689	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50648
1149280	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50648
1149016	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50648
1148816	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50780
1148105	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50648
1148153	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50780
1146095	dotnet/sdk	Microsoft.NET.Publish.Tests.dll.6.WorkItemExecution	#50648

Summary

24-Hour Hit Count	7-Day Hit Count	1-Month Count
14	26	26

[dsplaisted]

@dotnet/illink @agocke We are seeing failures where the GenerateBundle task is failing because it cannot access the singlnefilehost.exe file. We added retry logic because we thought maybe the issues were caused by defender. I thought that helped, but now the issue is happening pretty consistently, so it may be a product issue.

Interestingly, it seems to only fail on Mac OS and Linux when bundling a Windows app. I can't remember if it was failing on Windows before we added the retry logic or not.

Can someone investigate this?

I'm also wondering whether we should merge this codeflow PR which is blocked by the failure. That's where I've seen the failure most consistently recently, so it's possible there's a code change coming in that made the problem worse.

[agocke]

@jtschuster can you take a look?

[dsplaisted]

Ping @jtschuster, any progress on this? I just noticed it in #50876

[agocke]

I'm going to load balance a bit. @sbomer can you look instead?

[jtschuster]

Still investigating, but I am able to repro locally on a mac, but only on the first run of the test. Subsequent runs use the same path for the tmp project and don't repro. It's also interesting that it's failing on a read and not a write.