iPhone not uploading photos to iCloud Photo Library. Why?

After lots of digging around (and trial and error based on what I found), I discovered that all you have to do is delete the specific Moment from your Photos Collection that is the culprit. But first those photos need to be backed up somehow.

Here is what I did. I plugged my phone into my Mac, with Photos open on the Mac, too. I imported all the photos in the suspect Moment "album" in Photos on my phone into Photos on the Mac via the import button. I made sure all 300 photos (all the photos I took that day or "moment") were showing up in Photos on my Mac before I deleted them off my iPhone. I noticed that once I imported them manually via Photos on the Mac, they finally showed up in iCloud Photos, as well as in Photos on my iPad, which are all synced together (my Mac, my iPad and my iPhone should all automatically upload any new photo content to iCloud... as would normally happen automatically on my phone, but wasn't today).

I figured out which Moment was suspect by two observations. One (the most obvious clue), the automatic upload to iCloud that usually occurs with my Moment "albums" stopped working today... on this particular Moment upload attempt from today. The other thing that clued me in was the fact that if I made any changes to any other Moment, the change would happen across the board on all devices... So, for instance, if in an older Moment, I deleted a photo, it then would come out of the Moment "album" on the other devices as well. However, any changes I made today's Moment (that I suspected was the problem) would not happen across other devices, even after I manually imported all pictures from that Moment into Photos on the Mac... which, incidentally, populated the Moment for that date on my other devices, but only because it was syncing with my Mac where I manually added the photos. In other words, I could manually import the suspect photos from my iPhone into the Photos app on my Mac, and then iCloud and my iPad synced with the Photos app on my Mac, but wouldn't auto sync with that Moment in Photos on my iPhone. So, if I had deleted a photo from the Moment in Photos on the Mac, it would have come out of the Moment "album" on the iPad and in iCloud as well. But if I deleted it from the Moment in Photos on my iPhone, that was not the case.

Somewhere, I read that one file could have gone corrupt in the auto upload process, keeping the entire album from working, and causing Photos on the iPhone to say it's uploading many photos, even though it wasn't. (For me, it was saying it was uploading 13,000+ photos. It was just all mixed up until I deleted that entire Moment.

Knowing every photo from today was in Photos in all the other three places (iPad, iMac and iCloud), I deleted the entire Moment "album" from my iPhone and restarted my phone. After that, everything was working again and went back to normal. And because all are devices are synced, what I deleted was immediately added back onto my phone via iCloud.

Hope that helps!

You DON'T need to turn off iCloud and delete every photo off your phone as some suggest. You just need to figure out when the problem started so that you can figure out which Moment "album" is the culprit, and then delete just that Moment.

Thank you very much for this detailed explanation! This was really helpful. I'm going to try this!

You're a legend mate, this helped me INSTANTLY.