OS X Mountain Lion: Back up your Mac
Time Machine keeps a copy of everything on your disk, and saves “snapshots” of files that have changed so you can revisit files as they appeared in the past. These snapshots are made hourly unless you turn Time Machine off. Time Machine stores the snapshots on your computer’s internal disk. If you accidentally delete or change a file, you can use Time Machine to recover it.
You should also back up your files to a location other than your internal disk, such as an external hard disk, a disk on your network, or a Time Capsule. That way, if anything ever happens to your internal disk or to your Mac, you can restore your entire system to another Mac, and get all your information back where it belongs in no time.
Choose a backup disk
- To choose an external drive as your backup disk, simply connect your computer to the drive. A message appears asking if you’d like to use that disk to back up your files. Click “Use as Backup Disk,” and Time Machine takes care of everything else.
- To use a network drive as your backup disk, make sure your computer and the drive are both turned on and available on the network, choose Apple menu > System Preferences, and then click Time Machine. Follow the instructions in Time Machine preferences to choose your backup disk.
For more information about choosing a backup disk, and to learn how to set encryption options, see this help topic:
Unless you turn off Time Machine, you can count on being able to bring back items you accidentally delete, revisit older versions of files you’ve changed, or, if necessary, recover your entire system. For detailed instructions, refer to these topics: