If by restart you mean shut it using the cross on top right corner? I couldn't see any other way. I have done that and re-eopened and clicked on Sync All. It says Syncing, then finishes and says 'Sync Never' again. I have also tried pausing sync, coming out, shutting the app (as above), opened it again, restarted sync, Clicked on Sync All, etc, still the same.
I have entries added via phone and they aren't being picked up on the new desktop either, it just dowloaded what was there when I first set it up and has not changed since . I see you can clear cache, which I haven't yet tried, would you recommend ?