Getting an access denied, even as admin or system account on a (corrupted) user folder you want to be renamed ? Well you can fix that on the next reboot, with the following trick
Navigate as an admin to the registry key located at :
Create a multiSZ named « PendingFileRenameOperations » (or edit the existing one and add two more lines). The two lines are (and hit enter for a final empty line, so total 3 lines:
Save that multiSZ and reboot, the folder will be renamed on next reboot.