TIMBARNES  After a series of problems with my Mac Pro (2008), I was forced to take my machine in to the local Apple store, where they re-installed the operating system. This helped, but did not solve all the problems. I found the machine was running very slowly, and there seemed to be a lot more disk activity than I was aware of. I had previously used the Disk Utility (it saw problems but could not fix them), and TechTool Deluxe (it made changes, but didn't solve the problems), I finally purchased DiskWarrior.

DiskWarrior was able to re-build the file system, and since using it my machine has been back to its original high levels of performance.

I don't know how it works, but in my experience, DiskWarrior was able to fix problems that other utilities could not. For that reason it receives my highest recommendation.  
(Version 4.1.1)

RYANMEDIAINC  Diskwarrior 4.1.1. saved the day. I used on a WD 500gb external hard drive and it worked like a charm - sort of. New users (like me) should note that the program needs to be saved into your applications folder, specifically UTILITIES folder (my first try kept giving me an error about changing permissions) but it was not necessary after getting it in the right folder.

Also newbies should know, when I did the first rebuild it came back with an error that it could not complete - I ran it again and it worked fine.

So while it has some learning curves, it did in the end do what it said it would do. I gave it a 4 out of 5 only because it required me to spend some extra time GOOGLING the problems I was having installing the program.

Now I can get back to work.... thank you DISKWARRIOR  
(Version 4.1.1)

DRDUL  I have come to regard DiskWarrior as an essential app. Sure it's pricey and there's no demo, but in my experience, the $100 cost has paid for itself many times over. I use DW every month or so to keep my Macs fit and trim. Most importantly, I always use DW before a OS upgrade, and every upgrade has been problem-free.

I used to run DW from the CD, but soon realized that it was much faster to run it from an external drive cloned with SuperDuper! Doing so also avoids the need to buy a newer version of the CD from Alsoft when you buy a new Mac.  
(Version 4.1.1)

SMTIPS  Pretty strange that using the Diskwarrior Preview navigation window to copy files from a hosed drive to a good one uses 100% processor of one core of a quad processor, yet copying the files across to the other drive by just opening the preview disk and using the finder uses a negligible amount of processor and copies faster.

Try it yourself.   
(Version 4.1.1)

JCRAIG  DiskWarrior saved my daughter's 12" PB. For some reason after an attempted restart, the machine got stuck at the gray screen/Apple logo. The machine also would not boot from a CD, nor Safe Boot. Running fsck in Single User mode, Disk Utility could not repair the volume. Only by running DiskWarrior on the Powerbook in Target Disk mode could the volume be repaired with no data loss. My college-age daughter has her beloved PB back and Dad doesn't have to spend a grand on a new MacBook ;-)

DiskWarrior fixes what others can't. It's indispensable if you ask me and will pay for itself the first time it saves your behind.  
(Version 4.1.1)

MARCO114  There is no demo of this software to even try out. I have used it in the past and it sometimes worked, but I am not gonna fork over money without being able to try it.  
(Version 4.1.1)

JHT69  As a follow-up to the review I just left. It work after operating the DW in target mode. I was lucky since I happened to have both Macs at home. It seemed to work with 10.5.6 but I was still not able to boot up from the disk. They need to clearly label their compatibility chart on their box. It's a valuable tool, but I'm still very disappointed by the confusing compatibility issues. They need to get their act together.  
(Version 4.1.1)

JHT69  I was having some real troubles with a new iMac that I just recently purchased. I'm fairly certain that it was corrupted files that transferred when I uploaded my files from a MacBook Pro that I use as well.

DiskWarrior got me up and running in no time. It's very straight forward with a couple clicks of the mouse. I'm only giving this app 4 stars since the version I bought v.4.1.1 would not boot up from the disk that I purchased. A bit of hunting on their site indicated that I needed revision 901 (for the latest generation of iMacs. The version I just purchased from the local Apple store was version 810.

A solution seemed within grasp as a friend recommended downloading the latest version (via CD update); but quickly eroded when the version I bought rejected the upgrade process. I searched for the coveted version 901 and came up with a giant goose egg in their search engine. It's a wonderful piece of software to have on hand should things start going wrong.

However, they need to get their act together on the whole version thing. Don't tell me you have a tech update for my specific machine and then make it damn near impossible to find.  
(Version 4.1.1)

RY.MA  The best tool of its art.  
(Version 4.1.1)

DONMONTALVO  Don't leave home without it.

Don Montalvo, NYC  
(Version 4.1.1)