Safely remove your external hard drive and then reconnect it again to reset their connection. Sometimes, a simple reset will can be the solution.
If that didn't resolve the issue, we suggest you run the Checkdsk.exe tool on the drives that you wanted to be backed up, and on the backup location.
- Click Start.
- Type cmd in the
Start Search box
- Right-click cmd.exe in the Programs list, and then click
Run as administrator. Enter administrator password if prompted, or click on
Continue.
- At a command prompt, type the following command, and then press
ENTER:
Chkdsk /R X:
Note*: In this command,X: is a placeholder that represents the drive letter of the volume that you want to check.*
- Press Y when you are prompted to check the disk the next time that the system restarts.
- Close all applications, and then restart the computer.
- After restarting your computer, repeat steps 1 through 4 for the other volume, and then rerun the backup operation.
Let us know how this turned out for you.