What happen when one gets to the Windows' Computer Management and wanted to change the drive letter and one cannot find the available drive letter.
Why?
The drive letter has been used by other devices. When we plug in a thumb drive for example, Windows will assign a drive letter and this letter is saved in the Windows' Registry.
How To Change?
There are always software available to overcome this problem. The easiest way I found is to amend the drive letter inside the Windows' Registry.