I am having painful issues with syncing Lightroom on the Mac.
Attempt 1 to fix it
The problems started where i found that LR mac had synced 21k photos but then got stuck on 800 newly imported photos. I followed the advice on this forum to delete the Lightroom mobile data by selecting Lightroom > Preferences > Lightroom mobile > Delete All Data. This deleted all 21k photos on iOS devices and in the cloud and allowed me to start syncing from the Mac again. I selected just a couple of collections to sync to the cloud and it successfully synced just under 900 photos. They appeared on the iOS devices and the web. Great. I assumed all was well...
Broken again
On iOS, moved some photos from one collection to a new collection and saw that the change did sync across to the web. BUT, it hasn't synced into LR on the Mac :-(
I looked around a bit more on iOS and found that the star ratings that were set on the Mac hadn't arrived on iOS.
To test things further, i changed the name of a collection on the mac and that change did appear on iOS and the web. I changed a collection name on iOS and it synced to the web, but not LR mac.
So, it seems that changes are syncing from LR Mac to the web, but now not the other way round. That's the exact opposite issue that i had previously.
Possible cause?
I am wondering whether these issues are caused by sync conflicts? Perhaps LR on mac hadn't finished it's sync to iOS, and this was the reason i couldn't see the star ratings on iOS? Perhaps it then halts all further data syncing for photos that it feels are in conflict? To be honest, WHO KNOWS?? In 2014 we're all used to most of our apps syncing data between devices. For some reason, Adobe have decided to give us users absolutely no information about incomplete or conflicted syncs. We just sit and witness the mess when the sync engine gets suck and we're left in the dark and forced to carry a ridiculous "Delete All Data" action to try and resolve the issue. Really, re-sycning 21k photos takes a lot of time and upload capacity, and is surely avoidable in this day and age???
Adobe, please fix your sync engine, give users more information when syncs have issues, and make it easy and pain free to resolve sync issues. At the moment, i'm not sure what i'm paying for (as i already owned LR 5 and subscribed to creative cloud just for the syncing).