You might not always be near your Time Machine backup drive when using your Mac notebook computer. When your backup drive isn't connected, Time Machine makes copies of the files you create, modify, or delete, and stores them on your startup drive. These copies are called local snapshots. After your backup drive becomes available, Time Machine copies the local snapshots from your startup drive to your backup drive so that they're stored in both places. You can recover files from local snapshots even when you're away from your backup drive.
View local snapshots
When you enter Time Machine, a timeline appears on the right side of the screen. Each dated tick mark in the timeline is a backup, and each backup has a color when you move the pointer over it:
OS X Yosemite or later
- A bright red tick mark is a backup that can be restored now, either from a local snapshot or your backup drive. When your backup drive isn't available, only the local snapshots are bright red.
- A dimmed red tick mark is a backup that can be restored from your backup drive after that drive becomes available. Until then, the stack of windows on the screen shows a blank window for that backup.
OS X Mavericks or earlier
- A gray tick mark is a backup that can be restored now from a local snapshot.
- A bright pink tick mark is a backup that can be restored now from your backup drive.
- A dimmed pink tick mark is a backup that can be restored from your backup drive after that drive becomes available. Until then, the stack of windows on the screen shows a blank window for that backup.
Learn how local snapshots use storage on your startup drive
To make sure that you have storage space when you need it, Time Machine creates and retains local snapshots only when there is plenty of free space on your startup drive:
- If less than 20% of the total storage space on your startup drive is available, Time Machine removes local snapshots, starting with the oldest, until you have more than 20% free space.
- If less than 10% or less than 5GB of storage space is available, Time Machine removes local snapshots more quickly. When only one snapshot remains, Time Machine stops creating new snapshots. As free space increases, Time Machine at first replaces the previous screenshot with a new one, then eventually resumes creating snapshots as normal.
Because Time Machine removes local snapshots as needed, Finder and Get Info windows don't include them in their calculations. To see how much storage space local snapshots are using, choose About This Mac from the Apple menu, then click Storage. The space used by local snapshots is labeled Backups.
- Local snapshots are automatically enabled when you turn on Time Machine, and they're disabled when you turn Time Machine off. One daily snapshot is saved for every 24 hours, beginning from the time you start or restart your computer. One weekly snapshot is saved for every week.
- Time Machine status in the menu bar doesn't change when Time Machine creates or modifies a local snapshot.
- Learn what to do if you can't back up or restore with Time Machine.