On Aug 12, 2008, at 7:17 PM, Epimedia wrote:

Hello, a bit of a problem with Dovecot. Version is 1.0.15 and is a
default install (no changes to config) from FC8 repository... except
that Dovecot is configured to use Maildir

I have a user on the system who uses the tags in Thunderbird
(Important, Personal etc). When she tags the messages they cannot be
deleted and their tags cannot be changed. When deleting a message
from the IMAP inbox it momentarily disappears and moves a copy to
the Trash but when the IMAP inbox is reloaded the message reappears.
The same happens when I try to change a tag: it comes back with the
previous tag.

Untagged messages can be freely deleted. Also, this problem does not
happen if the messages are in a IMAP folder. They can be freely
deleted.

The problem seems specific to Dovecot, not Thunderbird, as I am able
to tag and delete messages in another IMAP account. Also, accessing
the same IMAP account using OS X Mail the messages come back after
deleting them.

Where should I start looking for a solution to this problem?

Sounds pretty weird. But I guess I'd first look at the rawlog output
of what the clients send to Dovecot and what Dovecot sends back. Also
are there any error messages in Dovecot's logs? It kind of sounds like
the mailbox could be read-only, but there should be no difference
between expunging a message that has tags ("IMAP keywords") and that
doesn't have.