Press the Windows Key + X, and select the Command Prompt (Admin) option.
Click 'Yes' when you are presented with a UAC window requesting permission to launch the Command Prompt as Administrator.
In the new Command Prompt window, type chkdsk E: /f /r /x. (replace E with your drive letter).
This will check the drive for errors, and repair them. If it doesn't fix the problem there are other options, but try it first.