If my Mac OS or Mac OS X computer locks up, do I have to reboot?

If your Macintosh computer is running Mac OS X, you will probably be able to close a locked application without having to reboot your computer; in earlier versions from System 7 through Mac OS 9, you can probably quit the locked application and save your work in other applications, but then you will need to restart your computer. To close the locked application, press Cmd-Option-Esc simultaneously. In Mac OS X, in the Force Quit Applications window that appears, choose the frozen application, and click Force Quit (or Relaunch, if it's the Finder that has frozen). In Mac OS 9.x and earlier, just click Force Quit in the window that appears. This will usually close the locked application (without saving, however).

Once you have force quit the locked application, if you are still using Mac OS 9, you should immediately save your work in other open programs, close them, and restart your computer. Unfortunately, even in Mac OS X, sometimes you won't be able to force quit an application, and will have to reboot the computer.

Also see:

• In WordPerfect 8 or 9, how do I use the backup option?
• In Microsoft Word, how can I use the AutoRecover feature to restore a document?
• In Mac OS X, how do I quit an application that isn't responding?