Some builds spuriously fail with the following error message:
I think that there are only a few obvious possibilities here:
1. Jenkins is trying to use the same workspace twice at the same time, which would be a bug on Jenkins' part.
2. Some earlier operation crashed, and Jenkins should be automatically deleting the lock for us, because expecting the user to do this isn't really reasonable for a supposedly automated build system.
3. Some user was diddling with the workspace and deserves to have their lock broken, in which case refer to #2.