I've managed to revert from El Capitan to Yosemite on my MacBook Pro with relative ease. The only issue I experienced was with my Photos library. Apparently El Capitan converted the database and now I can not just copy that back over from my external drive like I did with iTunes. The good news is that I didn't even realize that I had that many photos on my MacBook, and they're probably dupes of what's on the other computer. My Mac Mini is a different story, though. I have lots of pictures on there (a couple thousand, perhaps) that I would hate to lose. Can someone recommend a proper backup procedure that will allow me to step backward with my Mac OS and still be able to keep those photos. I would prefer not to use iCloud, but would consider that IF I can restore from iCloud and then remove the online copies of those photos. Thanks in advance for any advice. EDIT: This is all being done with the intention of restoring or importing into Photos in Yosemite, with as much metadata surviving the process as possible. Thanks!