MacOS client: sync freezes

Today I’ve updated the client to version 2.5.1.

Now it doesn’t sync any more. It says “Preparing to sync” (German “Bereite Synchronisation vor”), but it won’t do nothing.

I’ve set up the sync folder from scratch several times, but always the same issue. Occasionally, for some folders, the client would upload a very few MB, but in the end the upload freezes again and won’t start again - even after rebooting the Mac.

Any ideas for possible reasons?

Meanwhile i removed my account and created it now (in the client). Adding folders to sync now lead to the message “There are unsolved conflict. Click for more details”. I’m clicking like hell, but details won’t show up…