Our build intermittently fails when we are trying to clean the workspace because a particular file is locked by the Jenkins java process.

All other files are removed except "version.txt" in which we store a product version number specific to the build.

The only thing different with this file compared to other build artifacts is that it is used by the build name setter plugin to rename the build based on the product version number.

{{<org.jenkinsci.plugins.buildnameupdater.BuildNameUpdater plugin="build-name-setter@1.5.1">
<buildName>version.txt</buildName>
<macroTemplate>#${BUILD_NUMBER}${ibm.dv.git_branch}</macroTemplate>
<fromFile>true</fromFile>
<fromMacro>true</fromMacro>
<macroFirst>true</macroFirst>
</org.jenkinsci.plugins.buildnameupdater.BuildNameUpdater>}}

I have no concrete evidence or reproduction step I'm afraid, sorry about that.
However it might be that there is an obvious issue with file closing so I thought I'd raise it with you