Lightroom classic 8 sync problems

Hallo, I had sync more than 15000 photos with lightroom classic (previous version 2018). Now I changed my Mac, and I have lightroom classic 8 installed. I copied my old catalogue from old Mac to my new Mac and I started sync. Lightroom now shows this kind of information: prior sync + 15000 photos to 0 and than re-start sync from 0 to 15000 and all photos present a sync error...at the end, all photos had sync errors. I tried to rebuilt sync, I tried to make some metadata change (for example make for all photos a star) and sync again, but problem is the same...prior sync all photo than all photo are re sync but with errors. No other forums help me.

Mac OS X Mojave and Lightroom 8