I faced the same issue and had to change from maildir to sdbox storage. The imap labels are now stored centrally per folder in an index file and not the filename anymore. Moving mails from one folder to another keeps the lable intact now.

Am 22.02.23 um 11:20 schrieb Alexis Ben Miloud--Josselin:

Hi,

I have an issue with e-mail tags/flags. The IMAP user is using Thunderbird or Roundcube with Thunderbird tags.

When the user (with an IMAP client) moves an e-mail from a folder to another, tags set on the e-mail are lost.

When we check the filesystem, we can see the "a" tag:

 -rw-rw---- 2 test mailusers 2498 Dec 29 15:31 'cur/1676643827.M563793P15241.<HOSTNAME>,S=2498,W=2551:2,a'

When we move the e-mail to another folder, the tag disappear:

 -rw-rw---- 2 test mailusers 2498 Dec 29 15:31 '.test/cur/1676644340.M214404P22014.<HOSTNAME>,S=2498,W=2551:2,'

In both folders, the dovecot-keywords file is:

 0 $LABEL1

The problem appeared after a major system upgrade (Debian 9 to 10). Dovecot version went from 2.2.27 to 2.3.4.1.

Some system informations:

 # dovecot --version
 2.3.4.1 (f79e8e7e4)
 # cat /etc/debian_version
 10.13
 # uname -a
 Linux <HOSTNAME> 4.19.0-23-amd64 #1 SMP Debian 4.19.269-1 (2022-12-20) x86_64 GNU/Linux
 # findmnt /var
 TARGET SOURCE    FSTYPE OPTIONS
 /var   /dev/vda3 ext4   rw,nosuid,relatime
 # findmnt /home
 TARGET SOURCE   FSTYPE OPTIONS
 /home  /dev/vdb ext4   rw,nosuid,nodev,noexec,relatime

The output of dovecot -n output is here (link expires in one year):

 https://paste.evolix.org/?96d46acaea638568#56g7AQLuzJxxy4xintpexJCPgiAAG23c38irQGMkV4Rp

Here are the operations I see on an e-mail file using strace:

 15507 link("/home/test/Maildir/cur/1672326270.M619318P11927.<HOSTNAME>,S=2498,W=2551:2,Sa", "/home/test/Maildir/.test/tmp/1672326456.M737812P15507.<HOSTNAME>") = 0
 15507 rename("/home/test/Maildir/.test/tmp/1672326456.M737812P15507.<HOSTNAME>", "/home/test/Maildir/.test/cur/1672326456.M737813P15507.<HOSTNAME>,S=2498,W=2551:2,S") = 0
 15507 unlink("/home/test/Maildir/cur/1672326270.M619318P11927.<HOSTNAME>,S=2498,W=2551:2,Sa") = 0

Setting mbox_lazy_writes to yes and/or unsetting mail_cache_fields doesn't change anything.

Any idea of what I am missing? Could this be a bug in Dovecot?

Thanks in advance,

-- Alexis Ben Miloud--Josselin abenmiloud@evolix.fr Evolix - Hébergement et Infogérance Open Source Marseille (37 rue Guibal, Pôle Média, 13003) / Paris / Montréal http://evolix.com | Twitter: @Evolix @EvolixNOC | http://blog.evolix.com

-- Cheers spi