I have the same issue. I work on 3 computers and since I can only activate CC on 2, I signed out from the iMac at home and signed in on my laptop. The sync worked great. But when I did the opposite, the iMac did not sync back. So all the files I deleted and the ones I created on the laptop don't appear on the iMac. I can see the files on the web and the laptop but not on the iMac! How is that even possible? Even weirder... when I change the name of files on the web, I then see that file appear on the iMac, but only that file, if it's a folder, it will appear, but empty... and I don't feel like renaming manually all the files I modified or added... any solution to make the iMac sync again?