From a troubleshooting viewpoint, one of the most useful OS X features is the OS X Recovery system. OS X Recovery replaces functionality previously accessed via an OS X installation DVD. This enables you to not only reinstall OS X but also to access a variety of administration and troubleshooting utilities. The primary difference is that the OS X Recovery system is, by default, located on the primary system disk. This allows easy “anytime” access to recovery utilities without the need for additional media.
In this lesson you will learn how to access OS X Recovery on both new Macs that came with OS X preinstalled and on systems that were upgraded to OS X. You will also briefly explore the utilities available from OS X Recovery. As long as you don’t make any permanent changes using the utilities in OS X Recovery, you can safely explore without damaging your primary OS X system.
Reference 4.1 Startup from OS X Recovery
Mac systems running OS X Mountain Lion, including both systems that shipped with OS X Mountain Lion and upgraded systems, include a hidden OS X Recovery system on the local system disk. To access this copy of OS X Recovery, simply restart the Mac while holding the Command-R keyboard shortcut. Once the OS X Recovery system fully starts, the OS X Utilities window appears. From there you can install (or reinstall) OS X and choose from a variety of maintenance applications.
If for some reason OS X Recovery doesn’t start or isn’t installed on the local system disk, there are two alternatives for accessing it:
If you have a Mac model released in mid-2010 or later—Assuming your Mac has the latest firmware updates, it’s capable of accessing OS X Internet Recovery. As the name implies, your late-model Mac can attempt to redownload the OS X Recovery system from Apple servers. If the local OS X Recovery system is missing, late-model Macs should automatically attempt to access OS X Internet Recovery. You can also force a system to start up to OS X Internet Recovery by holding the Command-Option-R keyboard shortcut.
- If you have an external OS X Recovery disk—Connect the OS X Recovery disk to your Mac and restart the Mac while holding the Option key. This opens the Mac computer’s Startup Manager, where you can use the arrow and Return keys or the mouse and trackpad to select the OS X Recovery HD. Reference section 4.3, “External OS X Recovery Disks,” covers this topic in greater detail.