Client 3.0 for Windows installed, but not starting

Server version: 19.0.1
Installed new client 3.0.0 yesterday (was 2.6.5). Last step: “run client” confirmed, it started sync.
Noticed that the client lost 2 od three synchronizations. Added the missing syncs. Client checked existing files on both sides (server/client).
Problem #1: Client started to copy ALL files again, though they existed in both sides. Because of poor internet connection estimated time was some hours.
Had to stop computer (shut down) in the meantime, started again this morning.
Problem #2: Client does not start at all. Errors protocolled in Windows syslog.
Reinstalled client 3.0: Same behaviour.
Reinstalled client 2.6.5: Same behaviour, no client, no sync.

Any suggestions?

Problem#2 resolved. The config file included entries for a sync folder type “Multifolders” which pointed to one of the regular folders. Removed the entire config lines, now it is working.

Thanks, I had the exact same problem - multifolders pointing to regular folder. So appears to be a bug. Removing worked.