Hi Team

Running Dovecot 2.3.21.1 in an ISP environment using dbox format as storage and built in dovecot replication to a secondary storage.

=> I know, it's not new - migration to 2.4 with completely replacing replication is pending.

For quite some time we are fighting issues with customers which are unable to delete IMAP folder. Those folder end up in status \NoSelect

When you issue a 'delete' for the folder, it is successful, but either the folder is back after logout/login or back right away when you list the folders.

Usual remedy: completely delete mail index of affected mailbox on both, primary and secondary storage, delete complete mail storage on secondary, resync with doveadm force-resync, cross filters.

Now I had a mailbox where even this did not solve the issue - but I noticed something weird.

. delete "mailbox" => OK . delete "mailbox" => OK . create "mailbox" => OK . create "mailbox" => Mailbox does already exist . delete "mailbox" => OK . delete "mailbox" => Mailbox does not exist

Now the Mailbox is gone from the file system and is not shown with list anymore.

Now I had a closer look at the next affected mailbox on the filesystem.

IMAP Foldername: LIST (\Noselect \HasNoChildren) "." INBOX.brokenmbox

Filesystem, directories: INBOX/brokenmbox/

=> There is no content, no hidden files inside the folder 'broeknmbox'

. delete "INBOX.brokenmbox" => OK

Checking Filesystem. Nothing changed, still the same.

. create "INBOX.brokenmbox" => OK

Checking Filesystem: Now we have: INBOX/broeknmbox/dbox-Mails/ all empty.

. delete "INBOX.brokenmbox" => OK

Checking Filesystem: broeknmbox/dbox-Mails/ are both gone within INBOX!

Conclusion: Dovecot seems to get confused, when a directory without dbox-Mails subdirectory exists, fails to delete such directories but still lists them as IMAP folders.

Is this a known bug? Is there anything which is know to cause this issue which we could tweak at our configuration?

Mit freundlichen Grüssen

-Benoît Panizzon-

I m p r o W a r e A G - Leiter Commerce Kunden

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