You'll want to read these Firefox help as well. """What precisely does “sync” mean with respect to transferring Firefox information between devices?" https://support.mozilla.org/gl/questions/1379470 "Sync data" https://support.mozilla.org/en-US/products/firefox/backup-recovery-and-sync/sync-data Also for the sync to work sometimes you need to leave both system logged into the sync Firefox for the sync data to populate between both devices. Firefox sync isn't instantons update it takes time for the sync to update to match both computers. So if you shutdown or close Firefox the sync will not update.