I have three individually named USB external drives that I connect to my computer. The fixed drives are A, C, D and E so the first available drive letter is F. When I plug in the drive that I've assigned to F (using Disk Management) it takes that letter and all is well. When I first started doing this, unplugging the drive would make that letter (F) available again, so if I plugged in that drive it would take the letter F again.

Now it doesn't do that. Each time I plug in again, it increments by one so it becomes G, then H and so on. It no longer "releases" its previous drive letter for re-use. Rebooting the computer resets it back to F but the same behaviour then repeats, i.e. incrementing each time. I get exactly the same behaviour from all other USB drives and from a memory card reader, so it's not a function of the drive hardware.

Someone previously suggested deleting the entire data from HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices]

but that seems very drastic. If I do delete all the data from that key, what will happen? Am I likely to have an unusable computer?

johngie

Personally if you do attempt to delete that key you should make a backup of the registry

Why do you want specific letters anyway?

My one at work assigns my drive as either E or D then when I get home it is H and all of my programs and shortcuts work

are you unplugging your drives using the 'safely remove hardware', or just pulling out the usb cable?

you could always run Process Explorer (link) and search for F: to see if any process is holding on to your drive

Edited May 29, 200620 yr by liquidguru

I think you can fix the drive letter by going to the device manager and setting the properties for the USB drive, while it is plugged in.