I had in my archive namespace[1] an INBOX folder and did not really get why it was there so I deleted it. Now this command generates map index error (doveadm force-resync does not fix it ;))
[@ ~]# doveadm -o namespace/4archives/location=mdbox_deleted:/home/mail-archive/testtest/mdbox/Archive -o mail_location=mdbox_deleted:/home/mail-archive/testtest/mdbox/Archive:INDEX=/home/archiveindex/testtest/index mailbox status -u testtest 'messages vsize' 'INBOX'
doveadm(testtest): Error: mdbox map /home/archiveindex/testtest/index/storage/dovecot.map.index corrupted: Unexpectedly lost INBOX uid=1 map_uid=4726 doveadm(testtest): Error: Mailbox INBOX: Failed to lookup mailbox status: mdbox map /home/archiveindex/testtest/index/storage/dovecot.map.index corrupted: Unexpectedly lost INBOX uid=1 map_uid=4726
[1] namespace 4archives { disabled = no hidden = no ignore_on_failure = no inbox = no list = yes location = mdbox:/home/mail-archive/%u/Archive/:CONTROL=/home/mail-archive/%u/Archive/control:INDEX=/home/archiveindex/%u/index mailbox Archive { auto = create autoexpunge = 0 autoexpunge_max_mails = 0 comment = driver = special_use = \Archive } mailbox "Archived mail" { auto = no autoexpunge = 0 autoexpunge_max_mails = 0 comment = driver = special_use = \Archive } mailbox "Archived messages" { auto = no autoexpunge = 0 autoexpunge_max_mails = 0 comment = driver = special_use = \Archive } ... ... mailbox Archives { auto = no autoexpunge = 0 autoexpunge_max_mails = 0 comment = driver = special_use = \Archive } order = 0 prefix = Archive/ separator = / subscriptions = yes type = private }