reopen this thread in 2022, I have the same issue. Hover on top of the wheel shows "...Syncing files...2 remaining..." and it has been like that for days. Is there a way inspect those files to cancel/delete,...?
(Please start new threads for new issues — the thread you posted to was from 2010 and not remotely relevant. I've moved this to a new thread.)
Restart Zotero and try again, and if it still happens provide a Debug ID from Zotero startup through a few minutes of syncing, using the "Restart with Logging Enabled" option.
Upgrade Storage
Restart Zotero and try again, and if it still happens provide a Debug ID from Zotero startup through a few minutes of syncing, using the "Restart with Logging Enabled" option.