P: 10 Pictures do not sync.

I’m glad this issue has been resolved for some, but nearly a year later not only has it not been resolved for me but the gentleman from Adobe who was helping me (you know who you are) has stopped responding to me, with no explanation. Frankly, I’m fed up with Adobe “support” and if I could find alternatives to the products I now use, from a company where the word “support” actually had meaning, I’d switch. 

*alan_haynes thank you, this worked for me. Also, this was the only thing that worked. Rebuild Sync seems an overkill for one stuck file. Also, I don't see this in you recommendations, but I readded the stuck file to a synced collection, and it synced. Not right away, but it did.

That unfortunately did not work. I shutdown LR C, removed the "YourCatalogName Sync.lrdata" folder and restarted LRC, reactivated sync and all pictures were successfully sync. Definitely a bug to be solved. I captured an LRSync diagnostic file that I would love to provide to support.

This is currently the workaround that quickly resynced many pictures on my side.

I had images stuck on "Building smart preview for Lightroom ecosystem" and this worked for me as well, although it took maybe 5 or 10 minutes for 17 photos. I keep Lightroom updated, but version is:  

Lightroom Classic version: 10.1.1 [ 202101041610-8c69aa4e ]
Operating system: Windows 10 - Business Edition
Version: 10.0.19042

I've just installed the latest update and restarted my laptop.  Unfortunately, I am still having the same sync issues. I have 26 photos stuck syncing. They haven't synced to lightroom mobile at all. 

I have the same probem, but I am non able to find the 18 photos which does not syncr ( I think they are photos I edited in Photoshop 

For all following this thread, this is the only solution today that worked for me.

Kind regards,

Dieter

I'd like to offer a third choice to Alan's list, which is to delete the "YourCatalogName Sync.lrdata" folder wherever your catalog file is stored. It will recreate. That has reliably unstuck my recent encounters with this exact "Building Smart Preview" issue (even if it doesn't appear that way at first). It does not prevent recurrence of  the problem which Adobe clearly needs to fix. But it does seem to allow syncing to actually complete in a more satisyfing way.