Time Machine can back up your Mac's data to your AirPort Time Capsule, or to an external drive that is formatted as Mac OS Extended. It can also easily use more than one backup disk in OS X Mountain Lion.
Time Machine works with:
- AirPort Time Capsule's built-in hard drive (any model)
- External USB hard drive connected to AirPort Time Capsule (any model) or AirPort Extreme (802.11ac model only)
- An external hard drive connected to your Mac
Use the Time Machine pane of System Preferences to choose your backup disk(s).
Time Machine is not supported with USB hard drives that are connected to an AirPort Express or AirPort Extreme device.