I agree with @FreakinEurekan that it is probably a large video…
Once it gets past its constipation I am sure things will flow freely again.
That being said, this little nugget has lived with me for… Oh I dunno… years?
The 1 Item it cannot seem to sync is just an ordinary .jpg — not an untypically large file or anything odd.
It just hangs on in there… I delete it, I rename it… I edit it… nothing works. It just pops back up. 🤷🏻♂️
Maybe one day when I upgrade to a new Mac it will vanish.
I F-ing hate this about icloud photos. I think they do it on purpose to prevent people from transferring all their photos from one device to another and then canceling the subscription or something.
Whatever it is, I've seen this come up multiple times. They throttle hard when you try to transfer more than a certain amount.