About the System Photo Library
If you have multiple Photos libraries, at any given time there will be only one that is designated as the System Photo Library. This library is the one that is made available by OS X for other applications to access directly. This library will appear in the photo browser in apps like Mail, iMovie, and Pages, as well as other services like your screen saver preferences. Applications that offer to import into Photos will import into the system library. The system library is also the only library that can be synced with your iCloud photo library.
To specify which library you want to be the system photo library, open the library in Photos, open the preferences window, and click the “Use as System Photo Library” button. Simply opening a library in Photos will not switch the system photo library, so you can feel free to open and work with other libraries without changing which library is set as the system photo library.
For more information on the system photo library, visit this support article on Apple’s website.
Because PowerPhotos needs to use a different method to read the content of the system photo library, you may see some minor differences in behavior when viewing the system photo library versus your other photo libraries:
- Any photos you have marked as hidden using the Image > Hide Photo menu item in Photos will not be displayed in PowerPhotos, and cannot be copied to another library.
- There can be a delay between when you make changes in the system photo library, and when PowerPhotos is able to see those changes. If you’re seeing different content in PowerPhotos than you are in Photos itself, try quitting and reopening PowerPhotos, which should help load the most up to date content for the library.
- Some additional differences apply if you have iCloud Photo Library enabled.