About Time Machine local snapshots

When you use Time Machine on a Mac notebook computer, Time Machine saves some of its backups to your startup drive.

Your Mac notebook computer might not always be near your Time Machine backup drive, so Time Machine also saves some of its backups to your startup drive. These local snapshots are automatically enabled when you turn on Time Machine, and disabled when you turn Time Machine off. One daily snapshot is saved every 24 hours, beginning from the time you start or restart your computer. One weekly snapshot is saved every week. 

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.

Time Machine timeline

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 snapshot 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.

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