How to Use Photos for OS X and iCloud Photo Library with multiple Macs?

You can easily use Photos for OS X and iCloud Photo Library with multiple mac computers. You need to paired Photos for OS X with iCloud Photo Library's "Optimize Storage" feature. When you open "Photos" app for the first time on your Mac, the library should import automatically. If you get a message to create a new library, then your Photos Library will stored in another location on your Mac. So it will not open automatically, you need to open it manually.

Now make sure that iCloud Photo Library is turned ON after your library is imported on your Mac. To turn ON "iCloud Photo Library" on your Mac, open "Photos" app and select "Preferences" option. Click "iCloud" and then checkmark the box located infront of iCloud Photo Library. Now choose "Download Originals to this Mac" option too. If you choose this option, you will have one master copy of your photos on your Mac. "Download Originals to this Mac" feature allows you to keep a copy of all your original photos and videos on your Mac.

Open your other Mac and launch "Photos" app. If you have an iPhoto library on the second Mac, then import it into Photos app and then turn ON iCloud Photo Library. If you find some duplicate photos on each computer, then iCloud will resolve those conflicts when it sync. Once your sync process finished you will get just one version of your photos.

If you don't have an iPhoto library on your second Mac, open "Photos and create new library and then turn ON iCloud Photo Library. You can select "Optimize Mac Storage" option to save storage space on your second mac. If you turn ON "Optimized Storage" and have enough storage space on your Mac, then original photos will be stored on your Mac.