Although it is not recommend there are some times when you may need to change the letter of your Windows drive from C: to another letter or it may have changed by itself to another letter and you need to change it back to C:. In my case after an automated Windows installation my Windows drive letter had come up as D: so I wanted to change it to C:. The reason this had happened was due to a USB disk being connected while the install was taking place so it had labeled that as C: instead. To change the drive letter please follow the steps below:
- Go to start > run and type in “regedit” and press enter.
- Expand the folders to HKEY_LOCAL_MACHINE\SYSTEM\MountedDevices
- You should see something similar to the screen below. We are interested in the \DosDevices\ values.
![]( "Registry Mounted Devices")
- If you are in the same scenario as myself and something is already using the C: drive you will need to select it from the list and press F2 to edit the value. You should change this to a drive letter that is not in use which in my case would be “I:”. If you do not have a device using C: you can skip to the next step.
- You then need to find the value which has your current drive and edit that to be C:. So in my case I need to change “\DosDevices\D:” to “\DosDevices\C:”.
- You should now restart your computer and the drive letters should change. You do not need to worry about the boot.ini configuration as this is controlled using the disk and partition numbers rather than the drive letters.
If you get an access denied message while trying to change these values it may be due to the permissions on the registry key. To change this you should right click the “MountedDevices” folder on the left hand pane and go to permissions. You then need to ensure that the “Administrators” group has full control of the folder. If you have modified these settings you should then close the registry editor and re-open it for the settings to take full effect.
