I have been sharing my catalogue from my iMac 27 to my MacBook Pro using smart previews. I store my Catalogue in Dropbox and can organize and do basic edits on my MBP. The original raw files are stored on the v iMac but the catalogue is shared.
After upgrading to CC, launching LR on the MBP (CC on both computers) shows only gray where the previews should be. Badges and star ratings are there but no previews. Interestingly, the "synced" catalogue is visible
I rebuilt the smart previews on the iMac to no avail. All works normally on the iMac.
Hesitant to mess with the catalogue from the MBP as it is using the shared catalogue.