How to Recover a Corrupted External Hard Drive
A corrupt external hard drive is a USB drive with drive information that has become skewed, either through user error or malicious software. Recover the information contained on the external drive by fixing the damaged portion of the drive using the tools present in your computer's operating system. This generally takes less than 20 minutes to do.
Connect the external drive to a USB port on the computer.
Right-click "Start." Click "Explore."
Click "Computer," right-click the letter of the external drive, and click "Properties."
Click "Tools." Click "Check Now" under "Error Checking."
Click "Attempt recovery of bad sectors" and "Fix file system errors." Click "Start."