Run chkdsk from Windows command line
Do you have an external HDD that you would like to analyse with Windows's inbuilt chkdsk function? Here's the magic.
1. Type CMD in Run
2. In Windows 7 or Windows Vista right click on the cmd and select "Run as administrator" and Continue on the UAC screen if that appears.
3. Type the command chkdsk /f I: where /f represents force repair and I: the drive letter to be repaired. You can get the drive letter from Windows's disk management or My Computer.
Microsoft recommends that any data recovery procedures should be done BEFORE attempting chkdsk because chkdsk prioritizes fixing file system to data recovery and data loss may occur.