M through Z are almost never used on most Windows systems.
Windows will display a warning letting you know that some apps might rely on drive letters to run properly.
So if you plug in a USB flash drive to get data from it, it might be F: but the next time you plug it in, it might be E: or G: depending on the order you plug them in.
The neat thing is you can assign a permanent letter to a USB drive directly with Windows 7, 8.1, and Windows 10.
You can also now use fixed paths for that drive in apps—such as back up apps—that may require them.
Craig Rollins Using Partition Assistant Server, I was able to repair the problem via Remote Desktop and a Cisco IPSec VPN.
Windows will assign drive letters to external flash drives, SD cards, and other removable storage devices dynamically as you plug them in.
If you use a lot of different external storage devices throughout the day, having different letters assigned each time can become annoying and make things feel unorganized.
For the most part, you won’t have to worry about this.
But if you do have any apps in which you’ve specified another drive letter for this drive, you may need to change them. Back in the main Disk Management window, you should see the new drive letter assigned to the drive. From now on, when you disconnect and reconnect the drive, that new drive letter should persist.