DiskWarrior

DiskWarrior is a system recovery and maintenance tool for the Mac. It was designed to repair your system when you suffer directory errors that cripple your Mac and makes you lose important files and data.

It can recover files from failing hard drives as well.

I haven't had the please of seeing these directory errors and I consider myself lucky for that. I do know of people who constantly suffer them. DiskWarrior uses a different approach to recover your data when you face one of these errors. Instead of repairing the failing directory, it creates a new one and it restores as much data as possible from the bad one. This is a patent-pending technology that powers DiskWarrior. I can't attest to the performance of this app, because I don't have the errors that it fixes. But there are quite a few reviews that I read that say that DiskWarrior works. It even got a few awards, one from MacWorld. Also, DiskWarrior doesn't seem to be offering a trial of this app for users to test it. The full app is $99.95.