Windows 7 keeps losing drive letters

Solution 1:

I think it probably had to do with the windows saving different drive letters for different drives into its registry. The registry keys are: HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices

I guess if you delete the unused entries it may help... but you may as well ruin the system and need a reinstall if you somehow messed up with it..

so there you go...

Solution 2:

I'm using CCleaner to keep my registry all nice and tidy, and as a result, it seems to be wiping the drive letter assignment registry items. While this isn't a solution per se, it seems to me that you may be running into something similar since you're a repair shop and may be trying to keep your test systems squeaky with a daily scheduled registry sweep which could be causing the issue.