Hello,
In order to provide better guidance please let us know the model number of your drive.
Also I will recommend some basic troubleshooting steps:
Try connecting the drive to another computer to verify if you have the same issue. Also what error message do you get when you try to drag a file to it?
As a last troubleshooting step you can try writing zeros to the drive using Western Digital’s Data Lifeguard Diagnostics tool.
