How to startup your Mac from an external hard drive.

You'll need an external hard drive with a Mac operating system installed to startup your Mac from an external drive. PowerPC Macs (G4 or G5) require a FireWire external hard drive and Intel Macs can use FireWire or USB external hard drives. Read "How to create a bootable clone backup" to set up a complete backup of your system to boot off of.

1. Connect the external hard drive to your computer with the appropriate cable. Restart your computer and hold down the option key as the computer restarts.
2. A gray screen with two (or more) hard drives will appear. Select your backup drive.
3. The computer will then start up from your backup drive instead of its regular internal hard drive. You may notice activity lights flashing on the external drive.
4. If you’re running OS 10.4.6 or later, go to the Apple menu in the upper left corner and choose About This Mac. In the resulting window, make sure your backup drive is listed as the “Startup Disk.” If you’re running OS 10.4.5 or earlier, check that the backup drive is the first drive listed on the desktop. If your backup drive isn’t listed in one of these places, then you haven’t started up from the external drive, try again.
5. Once booted from the external hard drive, open a few files and applications to make sure everything is working. If everything looks good, you’re done! Shut down your computer, unplug the backup drive, and put the drive in a safe place. Don’t leave the clone connected to your Mac, since it can get confusing very quickly!

Published March 24, 2009 12:00 PM
Last modified on June 16, 2009 3:39 PM