We get this output regardless of if we have "Delete temporary JUnit files" checked or not. It also does not matter if we manually make sure generatedJUnitFiles is deleted or not.

If we check "Delete temporary JUnit files" xUnit is still unable to delete the directory.

C:\HudsonSlave\workspace\dotnet>exit 0
[TASKS] Scanning workspace files for tasks...
[WARNINGS] Parsing warnings in console log...
Archiving artifacts
[xUnit] [INFO] - Starting to record.
[xUnit] [WARNING] - Can't create the path /C:/HudsonSlave/workspace/dotnet/generatedJUnitFiles. Maybe the directory already exists.
[xUnit] [INFO] - Processing NUnit-Version N/A (default)
[xUnit] [INFO] - [NUnit-Version N/A (default)] - 1 test report file(s) were found with the pattern 'ProjectName.CoreTest\bin\Release\NUnitResults.xml' relative to 'C:\HudsonSlave\workspace\dotnet' for the testing framework 'NUnit-Version N/A (default)'.
[xUnit] [INFO] - Converting 'C:\HudsonSlave\workspace\dotnet\ProjectName.CoreTest\bin\Release\NUnitResults.xml' .
[xUnit] [WARNING] - Can't delete the file: C:\HudsonSlave\workspace\dotnet\generatedJUnitFiles\NUnit\TEST-1674223725.xml
[xUnit] [INFO] - Stopping recording.
Sending e-mails to: dev@website.com
Finished: UNSTABLE

See mail list thread in the submitted URL for complete screenshots of all important output and settings for one case of this problem.