OS X Mountain Lion: Reinstall OS X

Reinstall OS X

You can use the built-in recovery disk to install a new copy of OS X while keeping your files and user settings intact.

Important: You need to be connected to the Internet to reinstall OS X.
  1. Choose Apple menu > Restart. Once your Mac restarts (and the gray screen appears), hold down the Command (⌘) and R keys.
  2. If you’re not connected to the Internet, choose a network from the Wi-Fi menu (in the top-right corner of the screen).
  3. Select Reinstall OS X, and then click Continue.
  4. Follow the onscreen instructions. In the pane where you select a disk, select your current OS X disk (in most cases, it is the only one available).
  5. To start the installation, click Install.

You can also create an external recovery disk. For more information, see this Apple Support article:

About Recovery Disk Assistant

Last Modified: Aug 8, 2013
60% of people found this helpful.

Additional Product Support Information