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How do you move a Photos library to an external drive on a Mac?

By Kayabyte · Last updated 14 November 2026

Short answer: quit Photos, drag Photos Library.photoslibrary from your Pictures folder to the external drive, then hold Option while opening Photos and choose the library on the drive. The drive must be formatted APFS or Mac OS Extended (Journaled), must not be your Time Machine drive, and should have Ignore ownership on (details in the guide linked below). If the originals are in iCloud only, download them first.

Before you start

  1. Check originals. With Optimize Mac Storage on, the Mac may hold only smaller copies. In Photos, Settings, iCloud, choose Download Originals to this Mac and let it finish. See are your originals really on your Mac?
  2. Check space. Look at the library size in Finder (Get Info on the library) and make sure the drive has more free space than that.
  3. Check the drive format. Disk Utility shows APFS or Mac OS Extended (Journaled). exFAT and FAT drives are not suitable for a library Photos opens. A drive used for Time Machine is not suitable either.

Move it

  1. Quit Photos.
  2. In Finder open Pictures and drag Photos Library.photoslibrary to the drive. This copies it; wait until it finishes.
  3. Hold Option and open Photos, click Other Library and choose the copy on the drive.
  4. If you want it to be your System Photo Library (the one iCloud Photos uses), open Photos, Settings, General and click Use as System Photo Library.
  5. Check that photos and albums are there before you delete the original from the Mac.

If it will not open

Apple asks for the drive to be connected before Photos starts and for Ignore ownership to be on. See why a Photos library on an external drive will not open and Photos library on a NAS.

If you only want the photos, not a library

A library can only be read by Photos. For plain files, export originals into folders. See export Photos albums to folders. AlbumRescue writes album folders with original files, edited versions and .xmp sidecars from a library on a drive, an old Mac, a damaged copy or Time Machine, read only; the Mac App Store edition is USD 14.99 once, and the direct edition has a free scan. It cannot fetch originals that stayed in iCloud. AlbumRescue

Questions

Does moving the library delete it from my Mac? Dragging copies it. Delete the original only after you have checked the copy.

Will iCloud Photos keep working? Only if the library on the drive is set as the System Photo Library.

Is a second copy a backup? One copy on one drive is not a backup. See back up a Photos library without iCloud.

Apple, Mac, macOS, iCloud and Time Machine are trademarks of Apple Inc. AlbumRescue is made by Kayabyte and is not affiliated with or endorsed by Apple.