Solution to: The parameter is incorrect error when changing drive letters

Did you get the error “The parameter is incorrect” when you try to change the drive letters? Here’s what you have to do.

Windows gives you a warning message that some programs will not work when you change drive letters (only those that rely on drive letters) and that is a first indication of the problem. If you are currently running any programs, then it is very likely that you will get the error “The parameter is incorrect” when you try to change the letter

1. Step Reboot your PC
2. Step After boot-up close all tray programs and all backgrounds programs and if you know how check what processes are currently running using the task manager
3. Step Now open the disk manager again and try to change the drive letter again. This time you should not get the error “the parameter is incorrect”

4. Step If you still get the error, try this.

Changing Drive Letters via Registry

Important: It is important to backup you registry before you attempt this: Here’s how to create a working backup of your registry

1. Step Open the regedit editor by entering regedit into Run (Windows key + R)

2. Step Uncollapse HKEY_LOCAL_MACHINE\System\MountedDevices

3. Step In the right pane, scroll down until you see \DosDevices\C: etc.

4. Step Make a backup of all DosDevices and then delete the conflicting drive that you think may be causing problems (do not delete C: or your Windows partition)

5. Step You can also simply rename the registry key and replace H: for example with F: to change the drive letters manually and then reboot

6. Step Click on Rename and remove only the letter e.g. H and replace it with your new UNUSED drive letter e.g. Z