I am getting negative numbers for "last sync time". Manual sync seems to always take time even if no changes made to library. I have reset to Server from local copy without any change in behavior.
I am using Vista, Firefox 3.5.2 and Zotero 2.0b4. The problem persists after restart. Also, I have noticed that Sync and File Sync restart after completion (runs twice every time I sync)
I assume you get the same behavior after restarting Firefox/your computer?