With Thunderbird 3.1 I can now "delete" a folder which moves it to Trash. But I cannot remove the folder in Trash.
The following is from the Thunderbird log file: 248[6814c00]: 8103800:imap.kzone.ch:A:SendData: 64 rename "test10" "Trash/test10" 248[6814c00]: 8103800:imap.kzone.ch:A:CreateNewLineFromSocket: 64 OK Rename completed. 248[6814c00]: 8103800:imap.kzone.ch:S-Trash/test10:SendData: 70 delete "Trash/test10/" 248[6814c00]: 8103800:imap.kzone.ch:S-Trash/test10:CreateNewLineFromSocket: 70 NO Invalid mailbox name: Trash/test10/ I can confirm that dovecot cannot delete a folder if the name is ended with a slash. b list "Trash/x" * * LIST (\HasNoChildren) "/" "Trash/xx" * LIST (\HasNoChildren) "/" "Trash/x" b OK List completed. c delete "Trash/x" c OK Delete completed. d delete "Trash/xx/" d NO Invalid mailbox name: Trash/xx/ Let me know if that's a Thunderbird bug and I'll open a ticket with Thunderbird. (But I hope it's a dovecot bug as dovecot bugs actually get fixed, fast. :-) $ dovecot -n # 2.0.rc2: /etc/opt/dovecot/dovecot/dovecot.conf # OS: SunOS 5.10 i86pc zfs first_valid_uid = 100 mail_location = mdbox:/l/dovecot/%u/dbox passdb { driver = pam } protocols = imap service imap-login { inet_listener imap { port = 0 } } service imap { vsz_limit = 1073741824 } ssl = required ssl_cert = </etc/opt/dovecot/dovecot/certs/dovecot.pem ssl_key = </etc/opt/dovecot/dovecot/private/dovecot.pem userdb { driver = passwd } verbose_proctitle = yes