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Tips index

Boot from a CD/DVD (10.4/5)

The OS X installation disc is bootable and there are occasions where you will need to boot from it. For example, to run Disk Utility to repair disk faults. Once OS X has been installed on the hard disk drive though, you'll find that the Mac always starts from the hard disk, so how do you boot from the CD/DVD-Rom drive?

Insert the disc in the drive and shut down the Mac. Now switch on and hold down the C key until it starts booting up from the disc in the CD/DVD-Rom drive.

Boot from an external hard disk drive (10.4/5)

If you have an external hard disk drive, such as a USB drive that has OS X installed on it, you can boot the Mac from it instead of from the internal hard disk drive. There are two ways to do this and if if just want to do this occasionally you can simply hold down the Option key (the one with Alt on it), just after switching on the power. A list of boot devices is displayed and you can select the one you want by pressing the arrow keys and then boot from it by pressing the Return key.

Another way to boot from an alternative disk drive, and the best method if you want to make this permanent, is to set it in System Preferences. Click the Apple menu at the left-hand side of the menu bar and select System Preferences. Click Startup Disk in the System section and you'll see a list of boot devices. Select the one you want and then click Restart.

The advantage of the first method is that you can boot the Mac even if a fault on the internal disk prevents OS X from starting. The second method obviously requires a functioning OS X in order to select the boot device. You may be wondering how you make an external hard disk drive bootable. That's easy, just get a copy of SuperDuper or Carbon Copy Cloner and use either of them to make an exact copy of the internal hard disk drive.

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