Thanks, Adam! Attempting this again with HFS+ formatting.
I’m curious about you saying 8 hours doesn’t seem like enough time to download a Photos library. This library has about 14,000 photos. Wouldn’t the download time depend on the size of the library. Or is 8+ hours the norm no matter how big/small the library is?
Also, once you see that progress bar at the bottom get all the way across and there are visibly no more originals being downloaded, is it not safe to eject your drive yet? That’s what I did the first time. Don’t want to make the same mistake again – but I’m not even sure how I messed that part up!