February 2026 - dovecot

[Dovecot] batch convert mbox to maildir
by Netlink Tech 18 May '26

18 May '26

Hello, I have used mb2md for an individual user like this: su ~username cd ~ ./mb2md -m This converted /var/spool/mail/username mbox to /home/users/username/Maildir just as I expected. To convert 100s of users the same way would be a chore (su as each user for permissions, etc.). Is there a way to batch process all /var/spool/mail/$USER to /home/users/$USER/Maildir with the correct permissions/file owners for each user?

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Panic in logs
by Kamil Jońca 26 Apr '26

26 Apr '26

Recently I found in my lda logs: 2025-12-30T07:55:14.717927+01:00 alfa dovecot: lda(kjonca): Error: Raw backtrace: #1 [unw_get_proc_name() failed: -10] -> #2 i_syslog_fatal_handler[0x7f99a2351430] -> #3 i_panic[0x7f99a226d453] -> #4 [unw_get_proc_name() failed: -10] -> #5 [unw_get_proc_name() failed: -10] -> #6 [unw_get_proc_name() failed: -10] -> #7 buffer_append[0x7f99a2345270] -> #8 dregex_code_match_groups[0x7f99a233f1a0] -> #9 [unw_get_proc_name() failed: -10] -> #10 [unw_get_proc_name() failed: -10] -> #11 sieve_match_value[0x7f99a117f770] -> #12 sieve_match[0x7f99a117fa30] -> #13 [unw_get_proc_name() failed: -10] -> #14 sieve_interpreter_continue[0x7f99a117e100] -> #15 sieve_multiscript_run[0x7f99a1190330] -> #16 [unw_get_proc_name() failed: -10] -> #17 mail_deliver[0x7f99a27e54a0] -> #18 main[0x55e371c555e0] -> #19 __libc_start_call_main[0x7f99a1e29f00] -> #20 __libc_start_main_alias_2[0x7f99a1e29fa0] -> #21 _start[0x55e371c566a0] And sadly it seems, that mail is missing (it was passed to pipe program to further processing) KJ -- http://wolnelektury.pl/wesprzyj/teraz/ When you go out to buy, don't show your silver.

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mbox to maildir migration, same server?
by kjohnson＠eclypse.org 25 Apr '26

25 Apr '26

What is the recommended procedure to migrate from mbox to maildir on a server already running dovecot? Ideally, this procedure would convert messages in an existing mbox INBOX and in ~/mail mboxes (as defined in my dovecot configuration) to storage in a ~/Maildir. Some of the INBOXs are rather large -- 100's of MB (one of the reasons for migrating). What I have tried has not worked for me. Below, I describe what I tried, how I tested before I tried, what went wrong, and the current setup (pre-migration). What I tried: ============= stop exim4 service dovecot stop Make dovecot listen only locally, not to external connections. /etc/dovecot/local.conf protocol imap { listen = 127.0.0.1:143 ssl_listen = 127.0.0.1:993 } protocol pop3 { listen = 127.0.0.1:110 ssl_listen = 127.0.0.1:995 } Modify dovecot configuration for maildir: Watch capitalization! #in 10-mail.conf: mail_location = maildir:/home/%u/Maildir namespace inbox { separator = / } dovecot -n, to confirm results and perform limited syntax checking. service dovecot start for each user, in a bash script: dsync -v -u "$U" mirror "mbox:/home/$U/mail:INBOX=/var/mail/$U" (if the conversion worked for all users, then reconfigure exim to use maildir and restart it; reconfigure dovecot to listen to external interfaces and restart.) How I tested: ============= Before trying this on the real server, I set up a matching (same versions of Debian, Exim, and Dovecot) VM using mbox, with a couple of accounts. One using POP3, one using IMAP. The IMAP account was accessed from Claws and from Outlook. The test accounts had perhaps a dozen messages on the server. I tried the conversion procedure, and everything I tried worked flawlessly. (Yes, next time I will move some real inbox files from the live server). What went wrong: ================ I encountered two types of problems here. The first was several dsync warnings (username changed): dsync(example): Warning: Mailbox changes caused a desync. You may want to run dsync again: Remote lost mailbox GUID 21bfa11a81f11763ac150000d09efc50 (maybe it was just deleted?) As I understand it, this can result in some or all messages being downloaded again by clients. My understanding may be wrong. I also don't understand how the mailbox could have changed -- exim4 was stopped, dovecot is only listening on 127.0.0.1, and I am the only user who uses a local mail client on that system, and this was not my account. The second problem I encountered seems to match Debian Bug report logs - #1011238. In part of the discussion of that report, the reporter mentions adding -1 to the command, as shown: dsync -v -u "$U" mirror -1 "mbox:/home/$U/mail:INBOX=/var/mail/$U" While this seemed to eliminate the dsync panic of #1011238, as far as I can tell, no old messages were actually moved from the old mbox files to the new maildirs. At that point I restored the backup mbox files and undid the changes to dovecot and exim4. Current setup: ============== Debian 11.4 Exim 4.94.2-7 dovecot 1:2.3.13+dfsg1-2 The current setup with Dovecot was a successful migration from IMAP-UW in December 2020. Output from dovecot -n (the list of trusted networks has been removed) # 2.3.13 (89f716dc2): /etc/dovecot/dovecot.conf # Pigeonhole version 0.5.13 (cdd19fe3) # OS: Linux 5.10.0-16-686-pae i686 Debian 11.4 # Hostname: localhost auth_verbose = yes mail_location = mbox:~/mail:INBOX=/var/mail/%u mail_privileged_group = mail namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = } passdb { driver = pam } pop3_uidl_format = %08Xv%08Xu protocols = " imap pop3" ssl_cert = </etc/dovecot/dovecot.pem ssl_client_ca_dir = /etc/ssl/certs ssl_dh = # hidden, use -P to show it ssl_key = # hidden, use -P to show it userdb { driver = passwd } Thank you to anyone who read this far. Ken

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doveadm batch crash
by Jonathan Casiot 13 Apr '26

13 Apr '26

Hi I'm having an issue with doveadm batch - the following command always crashes: doveadm batch : mailbox status all inbox Whereas the following work as expected: doveadm mailbox status all inbox doveadm batch : mailbox list Any assistance gratefully received. Debug output from the crash: Debug: Loading modules from directory: /usr/lib64/dovecot Debug: Module loaded: /usr/lib64/dovecot/lib01_acl_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib10_mail_crypt_plugin.so Debug: Module loaded: /usr/lib64/dovecot/lib90_stats_plugin.so Debug: Loading modules from directory: /usr/lib64/dovecot/doveadm Debug: Module loaded: /usr/lib64/dovecot/doveadm/lib10_doveadm_acl_plugin.so Debug: Skipping module doveadm_expire_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_expire_plugin.so: undefined symbol: expire_set_deinit (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_quota_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib10_doveadm_quota_plugin.so: undefined symbol: quota_user_module (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_fts_lucene_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib20_doveadm_fts_lucene_plugin.so: undefined symbol: lucene_index_iter_deinit (this is usually intentional, so just ignore this message) Debug: Skipping module doveadm_fts_plugin, because dlopen() failed: /usr/lib64/dovecot/doveadm/lib20_doveadm_fts_plugin.so: undefined symbol: fts_user_get_language_list (this is usually intentional, so just ignore this message) Debug: Module loaded: /usr/lib64/dovecot/doveadm/libdoveadm_mail_crypt_plugin.so doveadm(jc): Debug: Effective uid=1001, gid=100, home=/home/jc doveadm(jc): Debug: acl: No acl_shared_dict setting - shared mailbox listing is disabled doveadm(jc): Debug: mail_crypt_plugin: mail_crypt_curve setting missing - generating EC keys disabled doveadm(jc): Debug: Namespace inbox: type=private, prefix=, sep=., inbox=yes, hidden=no, list=yes, subscriptions=yes location=mdbox:~/mdbox:ALT=~/Archive/tape/mdbox doveadm(jc): Debug: fs: root=/home/jc/mdbox, index=, indexpvt=, control=, inbox=, alt=/home/jc/Archive/tape/mdbox doveadm(jc): Debug: acl: initializing backend with data: vfile doveadm(jc): Debug: acl: acl username = jc doveadm(jc): Debug: acl: owner = 1 doveadm(jc): Debug: acl vfile: Global ACLs disabled doveadm(jc): Panic: file mail-storage.c: line 875 (mailbox_set_reason): assertion failed: (reason != NULL) doveadm(jc): Error: Raw backtrace: /usr/lib64/dovecot/libdovecot.so.0(+0xa0e9e) [0x7fc993023e9e] -> /usr/lib64/dovecot/libdovecot.so.0(default_fatal_handler+0x2a) [0x7fc993023f0a] -> /usr/lib64/dovecot/libdovecot.so.0(i_fatal+0) [0x7fc992fb3c97] -> /usr/lib64/dovecot/libdovecot-storage.so.0(+0x49856) [0x7fc993301856] -> /usr/bin/doveadm(+0x348e2) [0x5631dbb5f8e2] -> /usr/bin/doveadm(+0x2e1ad) [0x5631dbb591ad] -> /usr/bin/doveadm(+0x2bd2c) [0x5631dbb56d2c] -> /usr/bin/doveadm(+0x2c92a) [0x5631dbb5792a] -> /usr/bin/doveadm(doveadm_mail_try_run+0x215) [0x5631dbb58285] -> /usr/bin/doveadm(main+0x46a) [0x5631dbb473fa] -> /lib64/libc.so.6(__libc_start_main+0xf5) [0x7fc992bd83d5] -> /usr/bin/doveadm(+0x1c565) [0x5631dbb47565] Aborted (core dumped) And doveconf -n output: # 2.2.36 (1f10bfa63): /etc/dovecot/dovecot.conf # OS: Linux 3.10.0-957.1.3.el7.x86_64 x86_64 CentOS Linux release 7.6.1810 (Core) # Hostname: ### redacted ### first_valid_gid = 100 first_valid_uid = 1000 last_valid_gid = 100 last_valid_uid = 1999 listen = * login_greeting = IMAP ready login_log_format_elements = user=<%u> method=%m rip=%r lip=%l mpid=%e session=<%{session}> %k mail_attribute_dict = file:%h/mdbox/dovecot-attributes mail_location = mdbox:~/mdbox:ALT=~/Archive/tape/mdbox mail_plugins = acl stats mail_crypt mailbox_list_index = yes mdbox_rotate_size = 16 M namespace inbox { inbox = yes location = mailbox Drafts { special_use = \Drafts } mailbox Junk { special_use = \Junk } mailbox Sent { special_use = \Sent } mailbox "Sent Messages" { special_use = \Sent } mailbox Trash { special_use = \Trash } prefix = separator = . } passdb { driver = pam } plugin { acl = vfile mail_crypt_global_private_key = <### redacted ### mail_crypt_global_public_key = <### redacted ### mail_crypt_save_version = 2 stats_memory_limit = 16 M stats_refresh = 30 secs stats_track_cmds = yes } postmaster_address = ### redacted ### protocols = imap service auth { unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } } service imap-login { process_limit = 200 process_min_avail = 4 service_count = 1 } service stats { fifo_listener stats-mail { group = users mode = 01224 } } ssl = required ssl_cert = <### redacted ### ssl_key = # hidden, use -P to show it ssl_prefer_server_ciphers = yes ssl_protocols = !SSLv2 !SSLv3 !TLSv1 userdb { driver = passwd } verbose_proctitle = yes protocol imap { imap_idle_notify_interval = 10 mins imap_metadata = yes mail_max_userip_connections = 20 mail_plugins = acl stats mail_crypt imap_acl imap_stats } Regards, -- Jonathan

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[Dovecot] migration from IMAP/POP3 courier server to a remote dovecot server
by nik600 06 Apr '26

06 Apr '26

Dear all i'm planning a transparent migration from a courier server that provides both IMAP and POP3 access to users to a remote dovecot server with both IMAP and POP3 access. I have to migrate about 2500 users for 250 GB of space. I'm using dovecot 2.2.5.4 on debian6 squeeze. To make a transparent migration i have to maintain old IMAP UIDs and POP3 UIDs, so i've read http://wiki2.dovecot.org/Migration and http://wiki2.dovecot.org/Migration/Courier and http://wiki2.dovecot.org/Migration/Dsync And decided that probably the best tool to use is Dsync, as the courier-dovecot-migrate.pl<http://www.dovecot.org/tools/courier-dovecot-migrate.pl> script works only locally. I've tested the dsync following instructions reported above but after the migration of one test-account the client re-download messages. If i want to keep both IMAP UIDs and POP3 UIDs i have to sync both imapc and pop3c with two commands? doveadm -o imapc_user=foo -o pop3c_user=foo -o imapc_password=bar -o pop3c_password=bar backup -R -u user@domain imapc: doveadm -o imapc_user=foo -o pop3c_user=foo -o imapc_password=bar -o pop3c_password=bar backup -R -u user@domain pop3c: Or imapc is enough? Do you have any suggestion? Thanks -- /*************/ nik600 http://www.kumbe.it

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Error: ldap: auth_passdb_post settings
by Ruud Baart 21 Mar '26

21 Mar '26

Dovecot 2.4.1 works fine on my Debian Trixie server. I use LDAP as backend for the users. I don't have problems. Authentication works fine. However logging show every time the following line: auth-worker(<user name@domain,::1)<109040><3v5ddOlJvrgAAAAAAAAAAAAAAAAAAAAB>: request [7]: Error: ldap: auth_passdb_post settings: Failed to parse configuration: Failed to expand passdb_fields/password setting variables: ldap: No such attribute 'userpassword' The LDAP authentication works correct. So I don't understand this message. My correct working LDAP configuration in auth-ldap.conf.ext: passdb ldap { passdb_use_worker = yes passdb_ldap_filter = (&(objectClass=PromptMailUser)(accountStatus=TRUE)(mailDeliveryaddress=%{user})) ldap_bind = yes fields { user = %{ldap:mailDeliveryaddress} password = %{ldap:userPassword} } } userdb ldap { userdb_use_worker = yes userdb_ldap_filter = (&(objectClass=PromptMailUser)(accountStatus=TRUE)(mailDeliveryaddress=%{user})) fields { home = %{ldap:mailBase} mail = %{ldap:mailMessageStore} mail_path = %{ldap:mailMessageStore} quota_storage_size = %{ldap:dovecotQuota} } }

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shared mailbox error
by Marc 19 Mar '26

19 Mar '26

I am getting this error. This file does not exist. Error: t_readlink(/xxxxxx/dbox-alt-root) failed: readlink() failed: Permission denied

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How to declare port 143
by Steve Litt 10 Mar '26

10 Mar '26

Hi all, I have Dovecot 2.4.2 working (plain text only) on my Qemu virtual machine, with Claws-Mail able to work with all its files. However, I want to declare the Dovecot server as running on Port 143, and when I do, I dovecot -F throws the error message shown later in this message. If I comment out the explicit port declaration, it works fine, and I want to know why. To the best of my knowledge, my declaration of port 143 exactly matches your 2.4.2 documentation: The following is my attempt to tell Dovecot to serve *explicitly* at port 143: =============================================== # My Dovecot server will operate on Localhost listen = 127.0.0.1 service imap { inet_listener imap-login { port = 143 } # inet_listener imaps { # port = 993 # ssl = yes # } } =============================================== The following is the result: =============================================== [root@dovecotvoid ~]# dovecot -F doveconf: Fatal: Error in configuration file /etc/dovecot/dovecot.conf: duplicate listener: 143:127.0.0.1 [root@dovecotvoid ~]# =============================================== If I comment out the port = 143, it works. Why is it griping about a duplicate listener? At the bottom of this email is the entire dovecot.conf and the result of dovecot -n, and there are no sub-configuration files in conf.d : =============================================== # Start new configs with the latest Dovecot version numbers here: dovecot_config_version = 2.4.2 # Must be current version dovecot_storage_version = 2.4.2 # Must be current version or earlier # 2.3 is minimum # I only want imap protocols { imap = yes lmtp = no pop3 = no } # My Dovecot server will operate on Localhost listen = 127.0.0.1 service imap { inet_listener imap-login { port = 143 } # inet_listener imaps { # port = 993 # ssl = yes # } } # mail_home is only for virtual users # A virtual user is a user with no system account # I have no virtual users, so I've commented out mail_home. #mail_home = /srv/mail/%{user} # mail_driver is the storage format mail_driver = maildir # mail_path is location of top of storage data # WARNING: For troubleshooting be prepared to switch # to literal location of ~ mail_path = ~/mail/Maildir # In my case # mail_home is the home directory of the user identified as ~ # WARNING: system users have no ~ without it. mail_home = /home/slitt # You need a log you can locate # There might not be a log_path=/var/log/dovecot.log #mail_uid = slitt #mail_gid = slitt mail_uid = vmail mail_gid = vmail # By default first_valid_uid is 500. #If your vmail user's UID is smaller, # you need to modify this: #first_valid_uid = uid-number-of-vmail-user namespace inbox { inbox = yes separator = / } # Authenticate as system users: passdb pam { driver = pam #driver = passwd } userdb passwd { driver = passwd } #ssl_server_cert_file = /etc/dovecot/ssl-cert.pem #ssl_server_key_file = /etc/dovecot/ssl-key.pem =============================================== The following is the output of dovecot -n: =============================================== # 2.4.2 (0962ed2104): /etc/dovecot/dovecot.conf # OS: Linux 6.12.71_1 x86_64 # Hostname: dovecotvoid dovecot_config_version = 2.4.2 dovecot_storage_version = 2.4.2 listen = 127.0.0.1 log_path = /var/log/dovecot.log mail_driver = maildir mail_gid = vmail mail_home = /home/slitt mail_path = ~/mail/Maildir mail_uid = vmail protocols { imap = yes lmtp = no pop3 = no } service imap { inet_listener imap-login { port = 143 } } namespace inbox { inbox = yes separator = / } passdb pam { driver = pam } userdb passwd { driver = passwd } ===============================================

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Dovecot 2.4 doveadm_worker_count corrupts tab-formatted output
by Philip Iezzi 08 Mar '26

08 Mar '26

Hi there On a Dovecot 2.4.2 (Debian Bookworm) server with over 1300 users, I am using the following config to retrieve quota usage information with doveadm: --------------------------------------- quota "User quota" { } mail_plugins = quota acl mail_log notify userdb sql { iterate_query = SELECT username AS user, CONCAT(quota, 'M') AS quota_storage_size FROM mailaccounts WHERE active = 1 query = \ SELECT '/var/vmail/%{user | domain}/%{user | username}' AS home, 'vmail' AS uid, 'vmail' AS gid, CONCAT(quota, 'M') AS quota_storage_size \ FROM mailaccounts \ WHERE username = '%{user}' AND (active = 1 OR transport_suspended = 0) } --------------------------------------- Initially, I had to run `doveadm quota recalc -A` to recalc quotas and populate the `count` quota driver which is enabled by default for "User quota". But still, it took roughly 20ms per single user or 15-20s for all users: $ time doveadm -f tab quota get -u demo(a)example.com real 0m0.020s $ time doveadm -f tab quota get -A real 0m16.800s Now, to greatly speed this up, I have introduced parallel processing: doveadm_worker_count = 4 Like this, `doveadm -f tab quota get -A` runs approx 10x faster, done in 1.5 - 2.5s But there is one major drawback which I assume to be a bug: # sane output without `doveadm_worker_count = 4` => always 6 fields demo(a)example.com User quota STORAGE 29 204800 0 demo(a)example.com User quota MESSAGE 1 - 0 # broken output with `doveadm_worker_count = 4` => sometimes 7 fields demo(a)example.com User quota STORAGE 29 2048 00 0 demo(a)example.com User quota MESSAGE 1 - 0 Somehow, the tab formatter does not play nicely together with parallel processing. On some output, the value gets split apart by an extra tab, e.g. '2024<TAB>00' in above example. Can you explain this corrupted data? Some kind of "output interleaving" seems to happen when running parallel workers. If I switch to json output (`doveadm -f json quota get -A`), this does not seem to happen and I always get valid JSON output, even with `doveadm_worker_count = 4`. Cheers, Philip

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Dovecot marking outgonig emails as unread
by stef204 03 Mar '26

03 Mar '26

Starting a few days ago, I have one email account where ALL outgoing emails are automatically marked as UNREAD. The message is sent, then copied to the "Sent" folder, and has status "unread". Then, a couple of minutes later, something happens where this message gets marked as UNREAD, without ANY interaction of client side. This occurs not matter the email client used, I have tried it with multiple email clients, both local and via web interface, the behavior does not change. This is via Dovevot on Cpanel. if I look at the [1]changelog, it is difficult to identify which changes could have triggered this as there seem to be changes impacting Dovecot almost with every update. I do not control the server myself, this is on a shared hosting plan; tech support has been willing to troubleshoot but is unable to locate the problem. This problem does NOT occur on other email accounts on the same domain, so it looks to me like some corruption or problem syncing flags perhaps? I am at a loss at the moment to fix this behavior. Any suggestions or ideas welcome. Thanks. References Visible links 1. https://docs.cpanel.net/changelogs/132-change-log/

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