In some cases, you need to restore the system or boot drive letter. What’s the situation and how to do that? Here, Partition Magic summarizes the possible cases and detailed steps to change the system/boot drive letter.

Cases to Restore the System or Boot Drive Letter

Generally speaking, it is not recommended to change the system/boot drive letter, especially if the drive letter is the same as when Windows was installed. You only need to do that when the drive letters get changed without any user intervention.

This situation may occur when you break a mirror volume or there’s a drive configuration change. In cases like that, you should restore the system or boot drive letter to match the initial installation. How to restore the system or boot drive letter? Detailed steps are shown as follows!

You can’t use the procedure offered in this post to change a drive whose drive letter hasn’t been changed. Otherwise, you may not be able to start your operating system properly. The procedure can only be used to recover from a drive letter change. Before starting the operation, you’d better back up Registry keys. To further safeguard your computer, make a Windows backup with MiniTool Partition Wizard – a piece of PC cloning software.

MiniTool Partition Wizard DemoClick to Download100%Clean & Safe

Further reading:

If your computer is unbootable due to drive letter chaos or missing, you need to boot it from a bootable USB drive and then restore the boot drive letter.

How to Restore the System or Boot Drive Letter

If you are going to restore the system or boot drive letter, pay attention to this section. It offers a full tutorial to change the system/boot drive letter.

The drive letter “D” in the tutorial refers to the wrong drive letter assigned to a volume, while the drive letter “C” is the new drive letter you want to change to or assign to the volume.

Step 1: Sign in as an administrator.

Step 2: Type regedt32.exe in the search box and then click the Open option under the

If you are prompted with a User Account Control window, click the Yes button to confirm the operation.
open Registry Editor from the Run window

Step 3: In the left panel of the Registry Editor window, follow the path below to locate the Registry key.


Step 4: Right-click on the MountedDevices key and choose Permissions.

choose Permissions

Step 5: Make sure that Administrators have full control and save the changes.

Step 6: Close Regedt32.exe and open Regedit.exe from the search box. Then navigate to the MountedDevices key again.

Step 7: Find the drive letter to change on the right side of the window. In this scenario, we select “\DosDevices\C:”.

Step 8: Right-click “\DosDevices\C:”and hit Rename.

You must use Regedit instead of Regedt32 to rename this Registry key.
hit Rename

Step 9: Rename it to an unused drive letter like “\DosDevices\Z:”. By doing so, you can free up the drive letter C.

Step 10: Find the drive letter you want to change like “\DosDevices\D:”. Highlight it and rename it to the “\DosDevices\C:”.

Step 11: Then highlight “\DosDevices\Z:”and rename it to “\DosDevices\D:”.

Step 12: Close Regedit and start Regedt32. Then restore the permissions to the previous setting for Administrators. It should be Read Only.

Step 13: Restart the computer.

How to restore the system or boot drive letter? Simply follow the above steps to perform the operation.

Related articles:

Files with random numbers and letters in C drive

Lenovo SYSTEM_DRV partition issues

Remove/recover drive space indicator bar

Configure a low disk space alert

Up to now, steps to restore the boot drive letter have been shown to you. If you need to change the system/boot drive letter safely, follow the given steps in the post.

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