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, turn on iCloud Photo Library and use Optimize Mac Storage, or move your photo library to an external drive.
Before moving your library to an external drive, you should back up your photo library using Time Machine or by manually copying the library to an external storage device.
Prepare your drive
You can store your library on an external storage device, such as a USB or Thunderbolt drive formatted as APFS or Mac OS Extended (Journaled).1 Find out how to check the format of your external storage device.
To prevent data loss, 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.
Move your Photos library to an external storage device
- Quit Photos.
- In the Finder, go 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.
- 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.2
- After the move completes, double-click the Photos library in its new location to open it.
- If you use iCloud Photo Library, designate this library as the System Photo Library.
Open another Photos library
If you have multiple Photos libraries, here's how to open a different library:
- Quit Photos.
- Press and hold the Option key while you open Photos.
- Select the library that you want to open, then click Choose Library.
The next time you open Photos, this library opens until you open a different Photos 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.
1. You can't move your photo library to a disk that's used for Time Machine backups.
2. If the volume isn't formatted APFS or Mac OS 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.