Curious... are you seeing an error message at the bottom of the Photos window when the Photos tab is open and where you normally see "updating" but it now reads "no internet connection found" or similar?
...and you have a fully functioning Internet connection?
Just says updating and stays at that. Have done a fresh install of sierra (not beta) so will see what happens.
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I find it very hard to believe that two completely different computers, running two completely different operating systems, on a 'reliable' internet connection are having this problem and it's somehow a widespread bug completely unrelated to you specifically.
It's got to be a configuration issue or something similar. I had a similar problem with ONE Mac having this problem with Photos... but I would have been convinced it was me and not Apple had the problem occurred on all three of my Macs, my iPad and my iPhone.
By the way, in my case it took 3 days to sync/upload a 35GB Photos library... and the Photos app showed little to no progress at any given time. It just eventually showed up as done. Now that was when the feature was first released to the public, so I'm sure Apple's servers were saturated as it was. But the point is that it may just take some time, and you need to be patient.
Don't find it hard to believe as I'm telling you how it is
A. It is a realiable internet connection. No issues with any other service plus speed tests show above what I should be receiving.
B. Yes both completely different macs running completely different operating systems are having the exact same issue.
C. I've not said at any time that it is an apple issue or a bug. I've asked for advice as if you google, others have had the same issue but no answers.
D. Not a configuration issue if a fresh install
[doublepost=1500244822][/doublepost]All started to download now. 5 Mins to download 45gb of photo/video on MacBook Pro and iMac. Not changed anything or done anything different. Just left the app open like I have all week