Hi Arnold,

thanks for your assistance. I solved the issue right now by changing

prefix = Shared/%%u/
to
prefix = Shared/%%n/

This omits the @mydomain.de part which holds the dot causing the
trouble. Why this became a problem due to the update I wouldn't know.

Regards

Lothar

Am 22.07.2019 um 10:49 schrieb Arnold Opio Oree:

Hi Lothar,

I haven't yet had the opportunity to go deep into Dovecot engineering /
development, (so please correct me if necessary anyone).

I have experienced this exception where attempting to copy mailbox data
within a client from IMAP account to IMAP account, but I have not had
it cause a mailbox to become inaccessible.

The reason was because Maildir++ format uses the "." separator to
delineate child directories, and therefore the character is illegal in
mailbox names. The issue was addressed by either changing the
filesystem layout to LAYOUT=fs or by changing the mailbox format
altogether to e.g. sdbox.

 location = maildir:%%h:INDEX=%h/shared/%%u

I can see from your configuration that the LAYOUT is not set as fs, so
I would assume is still using Maildir++.

Perhaps this setting was lost during the upgrade?

Regards,

Arnold Opio Oree
Chief Executive Officer
Parallax Digital Technologies

arnoldoree@parallaxdt.com

http://www.parallaxdt.com

tel : +44 (0) 333 577 8587
fax : +44 (0) 20 8711 2477

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-----Original Message-----
From: Lothar Schilling via dovecot <dovecot@dovecot.org>
Reply-To: Lothar Schilling <ls@proasyl.de>
To: dovecot@dovecot.org
Subject: Character not allowed in mailbox name
Date: Mon, 22 Jul 2019 08:33:45 +0200

Hi everybody,

after an update this morning to dovecot 2.3.7 we cannot connect to our
shared mailboxes anymore. The error message as issued in Thunderbird:

"Character not allowed in mailbox name '.'"

I didn't change anything about the configuration. Output of dovecot -n:

[...]
namespace {
 list = children
 location = maildir:%%h:INDEX=%h/shared/%%u
 prefix = Shared/%%u/
 separator = /
 subscriptions = yes
 type = shared
}
[...]

Any help would be appreciated, thank you very much.

Lothar Schilling