I have DiskWarrior 4.1, Leopard 10.5.4, on a Macbook Pro with a brand new Seagate 200gb 7200RPM hard drive and 2gb of memory. It has three partitions (40gb main boot drive, 8gb backup boot drive, and 137gb media storage drive).

At first, DiskWarrior exceeded my expectations, which were high given its reputation, it was fast, stable, and worked exactly as advertised. But in the last 1-2 months, it has become, let's say unstable, to put it lightly. I'm not positive whether it began before or after the Leopard 10.5.4 update on June 30th, so I can't say with certainty that it was the cause. But it was close enough to be the likely source. I purchased DiskWarrior in March, on the same day the 4.1 update was released so I can't speak to previous versions.

Initially, the Graph, Rebuild, and Check Files & Folders functions started taking drastically longer to complete. The progress bar would freeze and skip for such long periods, it seemed frozen (I timed a 46 minute Rebuild of the main partition). I used force quit the first few times until I realized it had just become extremely slow. If I used the finder, switched to another app, hid or minimized DiskWarrior, I couldn't switch back to its window, unhide or maximize. Even if I didn't leave the app, I couldn't select anything in the menu bar without a delay of about 30 seconds, if at all. Basically, it was non-responsive while performing any function.

Recently if you can believe it, it's actually gotten worse. Now, instead of repairing my hard drive it's started damaging it. The last five times using DiskWarrior from both boot partitions resulted in two instances of crashing the computer (i.e. "Your computer needs to be restarted" message") and having to force shutdown with the power button, two instances of just the application unexpectedly quitting/crashing during a Rebuild, and one error message saying it was unable/failed to rebuild the disk, after which I clicked the cancel button to return to the main window and it crashed. Two of those times, Disk Utility found damage to the hard drive that needed repair.

I've reinstalled DiskWarrior from the CD three times and it still doesn't work. Whenever it reported a failure or inability to repair or rebuild a drive, I would then use TechTool Pro, Drive Genius or Disk Utility, and not once have they reported the same error or been unable to rebuild or test the same drive.

Full Disclosure: I'm no computer expert so its possible there's something I've done that is causing this problem. I like to think I know my way around computers more than your average person but the breadth of my knowledge pretty much ends where use of the programming language and the Terminal application begins. So if anyone can tell me if I'm missing something please let me know and I'll post a correction.