How to Fix a Corrupt External Hard Drive
Hard drive corruption is a virtually inevitable process that occurs as sectors within a hard drive become worn or damaged. Due to the common nature of this error, there are operating system utilities available to correct these failures and restore computer data. Much like their internal counterparts, external hard drives can also be scanned and recovered from corruptions over time.
Click the "Start" button located in the lower left corner of the Windows desktop.
Click the "My Computer" or "Computer" button located on the start menu.
Right-click the external hard drive's icon within the "My Computer" dialog box that appears.
Select the "Properties" heading from the context menu that appears.
Click the "Tools" tab in the upper portion of the properties dialog box.
Click the "Check now" button beneath the "Error checking" heading.
Ensure that all options have a checkmark next to their heading and click the "Start" button. This scans the entire hard drive for logical and physical sector errors and also recovers data from any bad sectors that are found. These bad sectors are also set so they do not allow further data to be written to them.