NONR, with nice=FALSE, makes a call to runmsge which should remove prior versions of the run directories. runmsge defines purge.dir(), which calls file.remove on the run contents, and then on the directory. But the directory is not removed. Windows help for file.remove says...

Unlike on Unix-alikes, ‘file’ here means a regular file and not, say, an empty directory.

Probably file.remove for the directory should be replaced with unlink.

Fixed in 3.2.13. 'unlink' for directory removal in purge.dir() (all platforms).