Your photo library holds all your photos, albums, slideshows, and print projects. If your photo library is large, and you want to free up storage space on your Mac, you can move your photo library to an external drive.
Before following these steps, you should back up your photo library using Time Machine or by manually copying the library to an external storage device.
You can also free up space on your Mac by using iCloud Photo Library and choosing to optimize storage, which stores your original photos and videos in iCloud and leaves smaller preview images on your Mac. Note: iCloud Photo Library isn't compatible with network drives.
Prepare your drive
You can store your library on an external storage device, such as a USB, FireWire, or Thunderbolt drive formatted as MacOS Extended (Journaled). Apple doesn't recommend storing photo libraries on external storage devices like SD cards and USB flash drives, or drives that are shared on a network.
You can't store your library on a disk that's used for Time Machine backups.
Move your Photos library to an external storage device
- Quit Photos for macOS.
- In the Finder, go to to the external drive where you want to store your library.
- In another Finder window, locate your Photos library. The default location is Users > [username] > Pictures, and it's named Photos Library.photoslibrary. You can keep the Pictures folder in the Finder sidebar by choosing Finder > Preferences > Sidebar and checking the Pictures checkbox.
- Drag your Photos library to its new location on the external drive. If you see an error, select your external drive's icon in the Finder, then choose File > Get Info. If the information under Sharing & Permissions isn't visible, click , then make sure the "Ignore ownership on this volume" checkbox is selected. If it's not selected, click to unlock it, enter an administrator name and password, then select the checkbox.
If this volume isn't formatted MacOS Extended (Journaled), or has been used for Time Machine backups but hasn't been erased, this checkbox will either not be present, or won't be selectable after unlocking. Erase and reformat the drive for this option to be available.
- After the move has completed, double click the Photos library in its new location to open it.
- If you use iCloud Photo Library, you'll need to designate this library as the System Photo Library so that you can use it with the Media Browser in other apps or with iCloud Photo Library.
Keep these things in mind when you select a different photo library:
- When you designate a new System Photo Library and turn iCloud Photo Library on again, the photos and videos on your Mac will merge with those you've already uploaded to iCloud Photo Library.
- Photos will continue to use the same library until you repeat the above steps to select a different one.
- Only one user can have a shared photo library open. If another user tries to open it, an alert message appears that says the library is already in use. You'll need to quit Photos from the first user account before the next user will be able to view or edit this library.
- If you're using iCloud Photo Library, you can't share the Photos library between user accounts. Sharing the library between user accounts is only available if you don't use iCloud Photo Library.
If you have a permissions issue with your photo library, you might be able to resolve the issue by using the Photos library repair tool.