My old mac booted from a 1TB Newertech MiniStack via Firewire 800. Your Mac will go back to booting to it’s primary startup disk next time you reboot. It won’t work for USB and FireWire drives, though.īooting to another volume using either of these methods is a one-time temporary change, so you don’t have to worry about altering any settings to reverse it. This will bypass the selection menu and immediately start from the disc. Rather than hold the Option key, you could instead just press & hold the C key if you’re booting from a CD or DVD disc. This is especially true of USB flash drives. The computer will start up from the chosen volume, but bear in mind performance will likely be much slower than when you normally operate your Mac. Use the keyboard arrows to choose your boot device, then press the Enter key. Continuing to hold this button down will bring up a menu where you can select a disc or drive to boot from. There easiest way to boot to any device other than a Mac’s internal hard drive is to press and hold the Option key immediately after hearing the Mac startup chime. These are all potential reasons for booting to an external device, among many others. Perhaps you’ve got a cloned backup of your entire Mac on an external hard drive and you want to make sure it’s bootable. Or maybe you’re trying to boot from a USB flash drive that has a clean install of OS X on it for troubleshooting purposes. Let’s say you need to use the Mac OS X installation disc that came with your computer to reformat the hard drive and put it back to factory settings.

Apple made it easy so all you need to know is just a simple keyboard command. Click the picture below for a larger version.At some point, you may find a need to boot your Mac from a disc or a drive other than the primary Mac OS X startup volume. After the dmg is restored to the external device, change your boot disk to this device and reboot.ĭragging the source and destination files can be a little confusing. You will lose any information you have in your external device in this process. – Drag your device from the left column to the Destination textbox – Select your external device in the left column of the utility – In the Utilities Folder in your Applications Folder select Disk Utility – Copy your dmg file to your current apple desktop. Restore the dmg file to an external deviceĪn external hard drive or an iPod in hard disk mode will serve as an excellent booting device as well. The media is expensive, but for many people this is the easiest option.īurn it and reboot to it. OS X is too large to fit on a single layer DVD however, many macbooks support burning dual layer DVDs. Installing OS X from a dmg file format instead of a DVD/CD format seems challenging.

With leopard testing and development, many people are having troubles installing from the supplied binary. Installing OS X from a DMG file can be difficult.

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