Msbuild reports MSB3021 from time to time

Question

I have a larget project and when I run msbuild, it reports below errors from time to time, like 5 out of 10 times it reports errors.
When it fails, I have to msbuild multiple times to get it built successfully.

I feel like it is due to some kind of parellal building which causing issues that when a project tries to access dll A, dll A might still be building so it reports the dll is locked by msbuild.exe.

Any idea?

Could not copy "D:\repo\MyRepo\target\dev\MyDir\debug\amd64\myTest.dll" to "d:\repo\MyRepo\Target\Distrib\MyDirOther\all\debug\amd64\myTest.dll". Exceeded retry count of 10. Failed. The file is locked by: "System (4), MSBuild.exe (11396), MSBuild.exe (11296)"
error MSB3021: Unable to copy file "D:\repo\MyRepo\target\dev\MyDir\debug\amd64\myTest.dll" to "d:\repo\MyRepo\Target\Distrib\MyDirOther\all\debug\amd64\myTest.dll". The process cannot access the file 'd:\repo\MyRepo\Target\Distrib\MyDirOther\all\debug\amd64\myTest.dll' because it is being used by another process.

Answer 1

Hi @Yu Lan ,

Welcome to Microsoft Q&A!

Please try the following steps:

1. Close all instances of Visual Studio
2. Delete the hidden .vs, bin and obj folders in the project folder
3. Relaunch your Visual Studio
4. Clean the solution and rebuild your project

Sincerely,
Anna

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Answer 2

Tried following and works for me:

1. close VS code
2. delete bin and obj folder in solution (for all projects)
3. dotnet run --configuration Release (we need to run in Release not debug)
   Its works
   try above steps and let me know
   thanks
   Rajiv Kumar
   rjkchaurasia@Stuff .com