Thunderbird Version 17.0.6 on Ubuntu 12.04.

The title says it all. I delete a mail account (Edit -> Account Settings -> select account -> Account Actions -> Remove Account -> OK), and the account folders disappear, but when Thunderbird is relaunched the account and its folders reappear. Even after reboot.

I've also posted on the Mozilla forum. I'll post back here if they give me a fix first.

Any help gratefully received. Thanks.