SolutionThis error comes up because the WMI repository has been reset too many times, and windows runs out of file names.
Under "C:\windows\system32\wbem\" you'll see a bunch of "repository.###" folders. These are the backups windows makes of the repository whenever you reset it. However this seems arbitrarily limited to three digits, so once it hits repository.999 it can no longer back the wmi repo up before the reset, so the reset fails.
The quick and dirty solution is to delete the various repository.### folders then try the reset again. Better solution is to find out why the repository is having to be reset so often and try to fix the underlying cause of the WMI corruption.
Full StoryI have a number of problems with WMI repositories becoming corrupt and requiring to be reset. I've never been able to track down the precise cause of these corruptions, so I've just been doing my best to keep things up and running.
Today I ran into a fun problem. I had a VM that wouldn't allow logins (or logins would take forever). Closer inspection saw that it had the telltale signs of WMI problems (1 CPU core maxed out, high memory usage). I rebooted to safe mode to try the reset, but the reset (winmgmt /resetrepository) failed with the error.
WMI repository reset failed. Windows cannot create a file if that file already exists
Or something along those lines. I forgot to write down the exact error before rebooting the machine, sorry.
Further investigation found the hundreds of "repository.###" folders in the wbem directory. Deleting these folders allowed the reset to run correctly. VM rebooted to normal mode without issue.