OS X Mountain Lion: Exclude items from a Time Machine backup
You can exclude items from a Time Machine backup to save space on your backup disk. If you’re using a different method to back up certain files and folders, you may want to exclude them as well.
- Choose Apple menu > System Preferences, and then click Time Machine.
- Click Options.
- To specify an item that shouldn’t be backed up, click Add (+), and then select one or more items. You can also drag items to the list. To remove an item from the list, select it, and then click Remove (-).
The backup disk is automatically included in the list of items that shouldn’t be backed up.
- Click Done.
If you choose to omit the System folder from backups, a message asks if you want to also exclude other system files. For more information, refer to this topic: