hello theja, there has been a change in the sync account system in firefox 29. when you have set-up your account before that (which is likely the case when your credentials weren't known once you tried to sign in to the new sync), you'll need your old username, password and recovery key in order to connect to the old account! if you have that information available you could try the following procedure: # disconnect from the new account through the sync panel in the firefox options. # enter '''about:config''' into the firefox address bar (confirm the info message in case it shows up), right-click somewhere in that page & create a new string preference named '''services.sync.username'''with a value like '''fake''' and restart firefox. # afterwards you should be able to connect to the old account through the firefox options > sync panel. if this worked and you could import your data this way, please log out of the old sync account again and reconnect to your new account.