Back up your photo library
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.
Move the photo library to an external drive
To share your photo library, you need to move the library to a volume where ownership is ignored.
If two or more users attempt to use the same library and the library isn't on a volume where ownership is ignored, you might see unexpected results. For example, you might not be able to see or edit certain photos, or open the library. Follow the steps below to make sure that each user has read/write access to the library.
- Connect an external USB, FireWire, or Thunderbolt drive which has enough free space to contain the library.
Be sure to choose a locally mounted drive. Storing your library on a network share can lead to poor performance, data corruption, or data loss.
- Select this drive in the Finder.
- Choose File > Get Info.
- In the Info window, find the Sharing & Permissions section. You might need to click the triangle next to Sharing & Permissions to see the details for this section.
- Click the lock in the lower-right corner of the Info window. Enter an administrator name and password when prompted.
- Select the option to Ignore ownership on this volume (usually selected by default).
If you've already selected this volume for use as a Time Machine backup, you won't be able to select the option to ignore permissions. Select a volume you're not using with Time Machine as the destination of your shared library.
- Copy your library to this drive. By default, libraries for Photos and iPhoto are located in the Pictures folder within your home folder.
Select the library in Photos or iPhoto
After you've moved your photo library to an external drive, you can select it for use in Photos or iPhoto:
- Hold down the Option key and open Photos or iPhoto.
- A list of available photo libraries appears. Select the library that you moved to a new location, and then click Choose Library.
To make sure that you select the correct library, look at the path that appears below the list of libraries. It should include the name of the external disk you moved the library to.
- If the library that you moved isn't in the list, click Other Library and find it in the file chooser.
- If you're using Photos, 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 (as in step 4 above) 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 or iPhoto 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 or iPhoto from the first user account before the next user will be able to view or edit this library.