[Editor's Note: This is an excerpt from, a new book for Mac users who want to travel beyond the basics. To learn more about the book!] It’s a good idea to have a bootable emergency drive on hand, just in case disaster strikes your Mac. An emergency drive (also referred to as an OS X Recovery Disk) can help you repair the hard disk, reinstall the operating system, and restore from a Time Machine backup to get your computer back fast. With previous versions of OS X, you could have used the installation DVD to fix problems. But OS X Mountain Lion is sold in the App Store as a digital download — no physical disk is provided. What’s a maintenance-minded Mac user to do? Create your own bootable OS X USB drive, of course!
Before You Start The obvious first step here is to download OS X Mountain Lion. Bootable Install DVD or USB Drive of OS X. Mac OS X Without a Recovery Disc.
It’s easy, and if you’ve already purchased OS X and have a USB drive that’s 1 GB or larger, it’s completely free. Carry it in your ￼￼￼￼￼￼￼￼￼￼pocket or put it on your keychain so it’s available if the worst-case scenario occurs. You’ll thank yourself for taking the time to complete this project. Evaluating Your Emergency Drive Options It can happen to any of us, even those who own brand-new Macs.
First your computer starts freezing infrequently, then crashing more often, and then it won’t start at all. For situations like this, you need an emergency drive on hand to start up your computer and troubleshoot the problem. • Emergency USB Drive: Creating a bootable USB drive is your safest bet. This device is self-contained and kept entirely separate from your computer — and any potential problems associated with it. But if you don’t want to create a USB drive, you may have access to two other types of emergency drives, depending on when you purchased your Mac. • Recovery HD: Every Mac running OS X Lion and later has a hidden Recovery HD partition that can be used to boot the computer and repair the hard disk.
(To use the Recovery HD partition as your startup disk, hold down Command-R at startup or, if that doesn’t work, option.) But the Recovery HD probably won’t work if the internal hard drive is damaged. When you can’t boot from the regular startup disk, chances are you won’t be able to boot from the Recovery HD either. • Internet Recovery: Macs purchased after OS X Lion was released have an additional feature called Internet Recovery, which works even if your internal hard drive is damaged. If there’s a problem with your computer, it can network-boot from Apple’s servers.
First, your computer’s memory and hard drive are checked for major issues. If none are found, your Mac downloads and boots from a Recovery HD image. But even if your Mac has this feature, you’ll still benefit from having an emergency drive, as it can take a while to download the Recovery HD partition. Purchasing a USB Drive for Your OS X Recovery Disk If you don't have a spare USB drive, you'll need to purchase one. We recommend the, which is a simple and affordable option available for less than $10.