Have you tried toggling the Use Subscription Folders, and/or
subscribing to said folders?
Quoting Jacob Beauregard <[log in to unmask]>:
> When I go to configure my UVM email in an previously unconfigured
> Thunderbird client, it seems to be missing the primary folders that
> I use, which I call "sent-mail" and "received-mail". I've also
> gotten some odd messages when trying to read, move, or delete things
> about those things not existing. Fortunately, this hasn't affected
> my @work configuration for Thunderbird.
> I have tried with and without the "mail/" directory in the advanced
> IMAP settings. Any ideas?
Dept. of Mathematics & Statistics
University of Vermont