Assigning Drive Letter to External drives

If you are using an external hard drive to automatically back up your data from your main drive. You should give the external hard drive a drive letter from the end of the alphabet instead of allowing it to choose a drive letter.
When you use a program such as Windows or some 3rd party back up software, you tell the software what drive to back the system up to. When you do, you tell the software what the drive letter is for that external drive. However, if you connect another USB device, it can actually take over the drive letter that was the drive letter of your external drive. For example...

You have an external drive (for sake of this example the drive is labeled WD) connected and the computer assigns it to drive letter G.
You are using a program to back up to your external drive on drive G
You then insert a flash drive
The computer can take the drive letter G away from the external hard drive and assign it to the flash drive. If this happens, the external will be H or some other drive letter.
However the backup software will not know the drive letter for the external drive has changed and it will still try to backup to G. You will either get an error, or only a part of it will be backed up to the flash drive (depending on how much space is available on the flash drive)

If that happens, you may get a notification that the backup didn't happen and you may not. Also you may overlook the notification. Therefore your system will not be backed up in the event of a crash.

To avoid the external drive from getting the drive letter changed without your knowledge, Change the drive letter for the external hard drive to drive letter at the end of the alphabet. If Z is taken, then choose Y or some other letter at the end of the alphabet.

For instructions on how to change the drive letter, click here

For info about external drives, click here