Disk Doctor is to Disk First Aid what BBEdit is to SimpleText. It will find problems with your disks that you didn�t even know were problems (more on this later). Sure, Disk First Aid (DFA) can fix minor errors with a missing custom icon here and there, but Disk Doctor can find and fix much more. Everything from bad b-trees to bad file modification dates fall under Disk Doctor�s �I Can Fix This� list, and that�s impressive.
Norton Disk Doctor from Norton Utilities.
Check for disk errors and repair them.
Better than ScanDisk.