OS X Mavericks: Time Machine problems

This article has been archived and is no longer updated by Apple.
Time Machine problems
Time Machine must create a new backup


If you see a message that you must create a new backup

The backup disk is unavailable or can’t be found or “mounted”


If Time Machine can’t find your backup disk

If you need a password to unlock your backup disk

Apple Support article: AirPort Time Capsule: Time Machine backups may not mount; "Backup volume cannot be found" may appear

An incomplete, interrupted, or failed backup occurred


If a Time Machine backup is interrupted

If Time Machine doesn’t back up certain files

Apple Support article: Time Machine stops backing up to external disk

Time Machine is slow or seems stuck


If your Time Machine backup disk runs out of space

If Time Machine is slow

If Time Machine remains in the “preparing” stage

General troubleshooting

Make sure your backup disk is plugged in, turned on, and securely connected to your Mac. If your backup disk is on a network, make sure both the disk and your Mac are connected to the network. If the network is experiencing problems, your backup disk may not be available.

Download and install all recent updates to OS X. If you have a Time Capsule, update it with the latest software and firmware.

Keep your Mac up to date

Apple Support article: About AirPort base station firmware updates

Last Modified: Oct 20, 2015

Additional Product Support Information