AppleJack: The Best Mac OS X Troubleshooting Tool

There are a lot of Mac OS X maintenance programs out there: Onyx, Cocktail, MacJanitor, SystemOptimizer, etc., but I want to put the spotlight on the one I feel is the best: AppleJack. While we've mentioned AppleJack in passing here at TUAW, it's never gotten the praise I feel its due.

AppleJack is free and open source. It runs a suite of unix tools on your boot volume to repair it (fsck), clean system/user caches, repair permissions, validate preferences files, and delete swap files. These are all common maintenance tasks that many/most of the Mac OS X maintenance programs do.

Unlike most of the other system maintenance utilities out there, AppleJack runs at the command line, specifically the CLI you get when you boot into Single-User Mode. This means that if your computer cannot boot to the GUI, but can still boot to Single-User Mode, you'll be able to run AppleJack's utilities. We have AppleJack installed on our lab and classroom computers and I've encountered quite a few machines like this, and in most cases, AppleJack has been able to fix the problem. It's faster to do this process than boot the computer from Firewire Target Disk Mode, or from a System CD, and run Disk Utility (essentially, fsck) to repair the boot volume.

AppleJack is currently at version 1.4.1 and works with Mac OS X 10.2 and above, including Tiger.