Eddy Winner: AppleJack 1.5
If your MacBook starts misbehaving and you're nowhere near a Genius Bar, your first instinct may be to reach for your OS X...Dan Frakes, Macworld.com
If your MacBook starts misbehaving and you're nowhere near a Genius Bar, your first instinct may be to reach for your OS X Install disc to run some tests. Until you realize you don't have the disc with you.
That's when AppleJack comes in handy. You just start your Mac in single-user mode (by holding down Command-S at startup), and AppleJack's easy-to-use interface lets you perform a slew of troubleshooting tasks--repairing your hard drive, testing RAM, repairing permissions, deleting cache files, and validating preferences files--without requiring a special disc or another startup volume. And because it's available before OS X loads, AppleJack works even when a problem keeps you from booting into OS X.
Read our full review of AppleJack 1.5 (payment requested; The Apotek).