When running Jenkins as a Windows service the integrity plugin checkout won't write any files to the workspace folders. Only the directories will be created ,but everything will be empty. The build log will report success though:
[...]
Populating clean workspace...
Successfully checked out 4 files!
[...]

This problem occurs only when running as a service! If I start Jenkins with batch and run the same configuration the checkout will work just fine.

I will attach the relevant part of the jenkins.err.log with debugging enabled.