Most of the time, your Mac is the picture of health—it crunches numbers, plays music, and tackles even the most difficult tasks without even a hiccup. But there are hundreds, maybe thousands, of things that can go wrong with such a complicated system.

Just as it pays to keep a first-aid kit in your cupboard, you’d be wise to keep this issue of Macworld in a desk drawer. After all, it’s hard to search the Web for answers when you can’t get your computer to start! With this guide to OS X first aid by your side, you’ll be able to quickly resolve the most-common Mac problems: freezes, crashes, startup woes, and kernel panics.