January 2026 - dovecot

Panic: file imap-sieve-storage.c: line 216 (imap_sieve_add_mailbox_event): assertion failed: (ismt->src_box == NULL || ismt->src_box == src_box)
by Christian Kivalo 28 Feb '26

28 Feb '26

Reposting my reply from a few days ago to a thread with the same panic message. I found this in my logs when some mails that got deleted on the phone were still visible in roundcube. I currently have three users that trigger the panic. One user with an iPad accounts for nearly all of the panics. The problem shows when the account is accessed from android (thunderbird) or ipad. The same accounts show no problems when beeing used with roundcube or thunderbird on windows. I enabled core dumps on 2026-01-14 and have ~8500 core dumps of the imap binary until now. What causes this error and how can I fix it? In the logs all I see is the users login, then the panic. # doveconf -n # 2.4.2-2+debian13 (0962ed2104): /etc/dovecot/dovecot.conf # Pigeonhole version 2.4.2-2+debian13 (767418c3) # OS: Linux 6.12.0-custom.kvm x86_64 Debian 13.3 ext4 2026-01-13T21:44:32.317609+01:00 uschi dovecot: imap-login: Logged in: user=<user(a)example.com>, method=PLAIN, rip=<IP1>, lip=<IP2>, mpid=4194077, TLS, session=<cpkID0tId7dUc9rl> 2026-01-13T21:44:38.455379+01:00 uschi dovecot: imap(user(a)example.com)<4194077><cpkID0tId7dUc9rl>: Panic: file imap-sieve-storage.c: line 216 (imap_sieve_add_mailbox_event): assertion failed: (ismt->src_box == NULL || ismt->src_box == src_box) 2026-01-13T21:44:38.458755+01:00 uschi dovecot: imap(user(a)example.com)<4194077><cpkID0tId7dUc9rl>: Error: Raw backtrace: #1 [unw_get_proc_name() failed: -10] -> #2 [unw_get_proc_name() failed: -10] -> #3 i_panic[0x7f6b6c46c2f6] -> #4 [unw_get_proc_name() failed: -10] -> #5 [unw_get_proc_name() failed: -10] -> #6 [unw_get_proc_name() failed: -10] -> #7 mailbox_save_alloc[0x7f6b6ca103c0] -> #8 [unw_get_proc_name() failed: -10] -> #9 command_exec[0x55654e677400] -> #10 [unw_get_proc_name() failed: -10] -> #11 [unw_get_proc_name() failed: -10] -> #12 [unw_get_proc_name() failed: -10] -> #13 client_handle_input[0x55654e67ddc0] -> #14 client_continue_pending_input[0x55654e67e0b0] -> #15 io_loop_call_io[0x7f6b6c565490] -> #16 io_loop_handler_run_internal[0x7f6b6c567230] -> #17 io_loop_handler_run[0x7f6b6c5673c0] -> #18 io_loop_run[0x7f6b6c5675a0] -> #19 master_service_run[0x7f6b6c4b27f0] -> #20 main[0x55654e6688a0] -> #21 [unw_get_proc_name() failed: -10] -> #22 __libc_start_main[0x7f6b6c234ce0] -> #23 _start[0x55654e668eb0] 2026-01-13T21:44:38.459536+01:00 uschi dovecot: imap(user(a)example.com)<4194077><cpkID0tId7dUc9rl>: Fatal: master: service(imap): child 4194077 killed with signal 6 (core dumps disabled - https://dovecot.org/bugreport.html#coredumps) # coredumpctl dump PID: 1071230 (imap) UID: 5000 (vmail) GID: 5000 (vmail) Signal: 6 (ABRT) Timestamp: Fri 2026-01-16 19:17:15 CET (2s ago) Command Line: $'dovecot/imap [user(a)example.com <IP redacted> UID MOVE]' Executable: /usr/lib/dovecot/imap Control Group: /system.slice/dovecot.service Unit: dovecot.service Slice: system.slice Boot ID: 3668d179bda340229a780d5d43e426c3 Machine ID: 05698baa30ae984c9bd014566e16da18 Hostname: uschi Storage: /var/lib/systemd/coredump/core.imap.5000.3668d179bda340229a780d5d43e426c3.1071230.1768587435000000.zst (present) Size on Disk: 1.1M Message: Process 1071230 (imap) of user 5000 dumped core. Module libgcc_s.so.1 from deb gcc-14-14.2.0-19.amd64 Module libstdc++.so.6 from deb gcc-14-14.2.0-19.amd64 Module libzstd.so.1 from deb libzstd-1.5.7+dfsg-1.amd64 Stack trace of thread 1071230: #0 0x00007fbd1ca9f95c n/a (libc.so.6 + 0x9495c) #1 0x00007fbd1ca4acc2 raise (libc.so.6 + 0x3fcc2) #2 0x00007fbd1ca334ac abort (libc.so.6 + 0x284ac) #3 0x00007fbd1cc6caa0 n/a (libdovecot.so.0 + 0x6caa0) #4 0x00007fbd1cd49e67 n/a (libdovecot.so.0 + 0x149e67) #5 0x00007fbd1cc6c3d0 i_panic (libdovecot.so.0 + 0x6c3d0) #6 0x00007fbd1c42f942 n/a (lib95_imap_sieve_plugin.so + 0x4942) #7 0x00007fbd1c431223 n/a (lib95_imap_sieve_plugin.so + 0x6223) #8 0x00007fbd1d258f10 n/a (libdovecot-storage.so.0 + 0x11bf10) #9 0x00007fbd1d1a843b mailbox_save_alloc (libdovecot-storage.so.0 + 0x6b43b) #10 0x00005590b7ed4a69 n/a (n/a + 0x0) ELF object binary architecture: AMD x86-64 -- Christian Kivalo

5 12

LDAP AD Quota override not working
by wt.forsaken＠gmail.com 26 Feb '26

26 Feb '26

Hi there, I'm testing the new version of Dovecot 2.4 in Debian 13 before upgrading to my customers and I'm having difficult on trying to override the user's quota. The LDAP base is from Samba4 AD and having been trying the following configuration: auth-ldap.conf.ext: ldap_uris = ldap://localhost ldap_auth_dn = cn=admin,dc=localdomain ldap_auth_dn_password = password ldap_base = ou=users, dc=localdomain passdb ldap { filter = (&(objectClass=person)(sAMAccountName=%{user})) bind = yes fields { userdb_quota_storage_size = %{ldap:telephoneNumber}B } } userdb prefetch { driver = prefetch } userdb ldap { fields { quota_storage_size = %{ldap:telephoneNumber}B } } 90-quota.conf mail_plugins { quota = yes } quota "User quota" { } quota_storage_size = 40M Since there is no quotaBytes in Samba AD, I'm testing to map the telephoneNumber parameters to override the quota, also I'm just testing a 40M to see how it works. Roundcube webmail can see the quota being overriden in its inferior bar, but when I send an email to the user which is above the quota, the journal log inform "failed to store into mailbox 'INBOX': Quota exceeded (mailbox for user is full)". I don't know how to override the quota, since in passdb section I used the "userdb_" prefix but it is not being passed to userdb when I input the "doveadm user ..." command. I don't know if I have been clear in my request, but I'd appreciate any help.

3 3

Panic in logs
by Kamil Jońca 22 Feb '26

22 Feb '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.

4 4

2.4.2 breaks user iterations for LDAP
by cpfeiffer＠rev-crew.info 20 Feb '26

20 Feb '26

Hello everyone, Due to the fix for CVE-2025-30189, routines like userdb_ldap_preinit() call auth_cache_parse_key_and_fields() unconditionally, with the eventually called auth_cache_parse_key_exclude() erroring if a cache key could not be constructed. It’s also noteworthy that this call happens regardless of whether use_cache is set or not, and as of such failing to construct a cache key would cause an error even if use_cache = no was set for that database. This is however an issue for user iteration with LDAP, as documented here LDAP | Dovecot CE <https://doc.dovecot.org/2.4.2/core/config/auth/databases/ldap.html#user-ite…> . Such a userdb only has iterate_filter fields that would inherently not be containing any user variables. The call to auth_cache_parse_key_and_fields() uses a combination of ldap_base and userdb_ldap_filter anyway (so whatever is in iterate_filter isn’t considered), and for an iteration userdb as described in the documentation, the latter would be empty. Alas, I ended up getting the rather confusing error * auth: Fatal: auth-cache: dc=rev-crew,dc=info: Cache key must contain at least one variable With dc=rev-crew,dc=info being my ldap_base setting for the iteration userdb. I’m not critically dependent on the user iteration, so I’ve commented the userdb out for now, but this would need fixing. Regards, Christian Pfeiffer Hello everyone, Due to the fix for CVE-2025-30189, routines like userdb_ldap_preinit() call auth_cache_parse_key_and_fields() unconditionally, with the eventually called auth_cache_parse_key_exclude() erroring if a cache key could not be constructed. It's also noteworthy that this call happens regardless of whether use_cache is set or not, and as of such failing to construct a cache key would cause an error even if use_cache = no was set for that database. This is however an issue for user iteration with LDAP, as documented here [1]LDAP | Dovecot CE. Such a userdb only has iterate_filter fields that would inherently not be containing any user variables. The call to auth_cache_parse_key_and_fields() uses a combination of ldap_base and userdb_ldap_filter anyway (so whatever is in iterate_filter isn't considered), and for an iteration userdb as described in the documentation, the latter would be empty. Alas, I ended up getting the rather confusing error o auth: Fatal: auth-cache: dc=rev-crew,dc=info: Cache key must contain at least one variable With dc=rev-crew,dc=info being my ldap_base setting for the iteration userdb. I'm not critically dependent on the user iteration, so I've commented the userdb out for now, but this would need fixing. Regards, Christian Pfeiffer References Visible links 1. https://doc.dovecot.org/2.4.2/core/config/auth/databases/ldap.html#user-ite…

4 5

dovecot 2.4 changes
by Curtis J Blank 18 Feb '26

18 Feb '26

I just did a Tumbleweed upgrade. then I had to fix dovecot. No warning that dovecot was going to break what so ever. Below is all the things I had to fix. And then I could not read my email in Thunderbird because you changed: mail_location = mbox:~/mail:INBOX=/var/spool/mail/%u to mail_driver = mbox mail_path = ~/mail mail_inbox_path = /var/spool/mail/%{user} and the "%u" to "%{user}" was the showstopper. What a crock of BS! I spent 3 hours determining the problem and then fixing dovecot because you decided to make major changes for no good reason. It worked just fine the way it was. You could have automated the changes by providing a utility that would make the changes the first time it started up after the upgrade. I had to try to start dovecot and when it failed to start look in the log and see the error and fix it. Over and over and over and over and over and over and over and... Like I said what a bunch of BS! Yes this is a rant. And maybe openSuSE's is too blame also. Jan 24 03:33:35 server dovecot[2223449]: doveconf: Fatal: Error in configuration file /etc/dovecot/dovecot.conf line 25: The first setting must be dovecot_config_version Jan 24 03:36:45 server dovecot[4626]: doveconf: Fatal: Error in configuration file /etc/dovecot/dovecot.conf line 25: The first setting must be dovecot_config_version Jan 24 03:46:10 server dovecot[21464]: doveconf: Fatal: Error in configuration file /etc/dovecot/dovecot.conf line 2: Invalid dovecot_config_version: Currently supported versions are: 2.4.0 2.4.1 2.4.2 Jan 24 03:48:45 server dovecot[22135]: doveconf: Fatal: Error in configuration file /etc/dovecot/dovecot.conf line 92: dict { } is missing section name Jan 24 03:51:47 server dovecot[28824]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/auth-system.conf.ext line 10: passdb { } is missing section name Jan 24 03:53:22 server dovecot[29258]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/auth-system.conf.ext line 10: passdb { } is missing section name Jan 24 03:55:26 server dovecot[29906]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/auth-system.conf.ext line 49: userdb { } is missing section name Jan 24 03:56:57 server dovecot[30179]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/10-director.conf line 40: inet_listener { } is missing section name Jan 24 03:58:37 server dovecot[30652]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/10-logging.conf line 64: Unknown section name: plugin Jan 24 04:01:32 server dovecot[37805]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/10-mail.conf line 31: mail_location: Unknown setting: mail_location Jan 24 04:05:30 server dovecot[38898]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/10-mail.conf line 32: mail_location: Unknown setting: mail_location Jan 24 04:06:35 server dovecot[39158]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/10-ssl.conf line 23: ssl_cert: Unknown setting: ssl_cert Jan 24 04:09:07 server dovecot[39707]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/10-ssl.conf line 25: ssl_server_cert_file: open(/etc/dovecot/conf.d/-----BEGIN CERTIFICATE----- Jan 24 04:09:07 server dovecot[39707]: doveconf: Fatal: -----END CERTIFICATE----- Jan 24 04:09:07 server dovecot[39707]: doveconf: Fatal: ) failed: File name too long Jan 24 04:14:52 server dovecot[47156]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/10-ssl.conf line 27: ssl_server_cert_file: open(/etc/dovecot/conf.d/-----BEGIN CERTIFICATE----- Jan 24 04:14:52 server dovecot[47156]: doveconf: Fatal: -----END CERTIFICATE----- Jan 24 04:14:52 server dovecot[47156]: doveconf: Fatal: ) failed: File name too long Jan 24 04:17:35 server dovecot[54187]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/10-ssl.conf line 72: ssl_dh: Unknown setting: ssl_dh Jan 24 04:19:04 server dovecot[54532]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/10-ssl.conf line 93: ssl_prefer_server_ciphers: Unknown setting: ssl_prefer_server_ciphers Jan 24 04:21:07 server dovecot[60961]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/90-acl.conf line 11: Unknown section name: plugin Jan 24 04:22:40 server dovecot[61409]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/90-acl.conf line 17: Unknown section name: plugin Jan 24 04:23:35 server dovecot[61624]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/90-plugin.conf line 9: Unknown section name: plugin Jan 24 04:24:40 server dovecot[61932]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/90-quota.conf line 17: Unknown section name: plugin Jan 24 04:25:38 server dovecot[62301]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/90-quota.conf line 41: Unknown section name: plugin Jan 24 04:26:12 server dovecot[62335]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/90-quota.conf line 69: Unknown section name: plugin Jan 24 04:26:42 server dovecot[62550]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/90-quota.conf line 78: Unknown section name: plugin Jan 24 04:27:05 server dovecot[62582]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/90-sieve-extprograms.conf line 9: Unknown section name: plugin Jan 24 04:28:11 server dovecot[62819]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/90-sieve.conf line 24: Unknown section name: plugin Jan 24 04:29:02 server dovecot[63099]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/90-sieve.conf line 39: sieve: Unknown setting: sieve Jan 24 04:36:01 server dovecot[71295]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/90-sieve.conf line 39: sieve: Unknown setting: sieve Jan 24 04:39:04 server dovecot[72067]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/90-sieve.conf line 40: sieve: Unknown setting: sieve (sieve_script_sieve or sieve_script_personal_sieve not found either.) Jan 24 04:47:39 server dovecot[86665]: doveconf: Fatal: Error in configuration file /etc/dovecot/dovecot.conf: ssl_options: unknown flag: 'no_compression' Jan 24 04:50:51 server dovecot[93375]: doveconf: Fatal: dovecot_storage_version setting must be set Jan 24 05:01:51 server dovecot[105836]: doveconf: Fatal: Error in configuration file /etc/dovecot/conf.d/10-mail.conf line 31: mail_location: Unknown setting: mail_location Jan 24 05:06:18 cjbnew dovecot: imap(bob)<107288><SOtYQyBJTOXAqBTz>: Error: Mailbox INBOX: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:0 mode=0755) Jan 24 05:06:18 cjbnew dovecot: imap(bob)<107288><SOtYQyBJTOXAqBTz>: Error: Mailbox INBOX: Failed to autocreate mailbox: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:0 mode=0755) Jan 24 05:06:18 cjbnew dovecot: imap(bob)<107289><9+pYQyBJTeXAqBTz>: Error: Mailbox INBOX: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:0 mode=0755) Jan 24 05:06:18 cjbnew dovecot: imap(bob)<10Jan 24 05:06:18 cjbnew dovecot: imap(bob)<107288><SOtYQyBJTOXAqBTz>: Error: Mailbox INBOX: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:0 mode=0755) Jan 24 05:06:18 cjbnew dovecot: imap(bob)<107288><SOtYQyBJTOXAqBTz>: Error: Mailbox INBOX: Failed to autocreate mailbox: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:0 mode=0755) Jan 24 05:06:18 cjbnew dovecot: imap(bob)<107289><9+pYQyBJTeXAqBTz>: Error: Mailbox INBOX: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:0 mode=0755) Jan 24 05:06:18 cjbnew dovecot: imap(bob)<107289><9+pYQyBJTeXAqBTz>: Error: Mailbox INBOX: Failed to autocreate mailbox: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:0 mode=07557289><9+pYQyBJTeXAqBTz>: Error: Mailbox INBOX: Failed to autocreate mailbox: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:0 mode=0755) Jan 24 05:08:38 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:0 mode=0755) Jan 24 05:08:38 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: Failed to autocreate mailbox: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:0 mode=0755) Jan 24 05:11:10 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:0 mode=0755) Jan 24 05:11:10 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: Failed to autocreate mailbox: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:0 mode=0755) Jan 24 05:15:09 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:473 mode=0755) Jan 24 05:15:09 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: Failed to autocreate mailbox: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, dir owned by 0:473 mode=0755) Jan 24 05:18:35 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, we're not in group 473(mail), dir owned by 0:473 mode=0775) Jan 24 05:18:35 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: Failed to autocreate mailbox: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, we're not in group 473(mail), dir owned by 0:473 mode=0775) Jan 24 05:19:09 cjbnew dovecot: imap(bob)<122933></apLcSBJaKrAqBTq>: Disconnected: Connection closed (SELECT finished 0.138 secs ago) in=102 out=787 deleted=0 expunged=0 trashed=0 hdr_count=0 hdr_bytes=0 body_count=0 body_bytes=0 Jan 24 05:19:58 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, we're not in group 473(mail), dir owned by 0:473 mode=0775) Jan 24 05:19:58 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: Failed to autocreate mailbox: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, we're not in group 473(mail), dir owned by 0:473 mode=0775) Jan 24 05:20:20 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, we're not in group 473(mail), dir owned by 0:473 mode=0775) Jan 24 05:20:20 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: Failed to autocreate mailbox: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, we're not in group 473(mail), dir owned by 0:473 mode=0775) Jan 24 05:21:17 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, we're not in group 473(mail), dir owned by 0:473 mode=0775) Jan 24 05:21:17 cjbnew dovecot: imap(bob)<107806><1/QbSyBJUOXAqBTz>: Error: Mailbox INBOX: Failed to autocreate mailbox: open(/var/spool/mail/%u) failed: Permission denied (euid=500(bob) egid=100(users) missing +w perm: /var/spool/mail, we're not in group 473(mail), dir owned by 0:473 mode=0775)

12 19

"Synchronization corrupted index header" with mdbox: thousands of deleted e-mails reappeared in INBOX
by Ákos Szőts 17 Feb '26

17 Feb '26

Hi everyone, Suddenly, the following messages appeared in my Dovecot error log: master: Warning: Killed with signal 15 (by pid=0 uid=0 code=kill) Error: Mailbox Trash: Synchronization corrupted index header [...]/Trash/dbox-Mails/dovecot.index: uidvalidity=0, but next_uid=73 Warning: Mailbox Trash: fscking index file [...]/Trash/dbox-Mails/dovecot.index Warning: mdbox([...]/mail/storage): rebuilding indexes: Mailbox Trash index was fsck'd Warning: mdbox([...]/mail/storage): fscking index file [...]/index/inbox/storage/dovecot.map.index Error: Mailbox INBOX: [...]/INBOX/dbox-Mails/dovecot.index reset, view is now inconsistent The first message is because I restarted the container. Since then, Thunderbird shows thousands of previously deleted e-mails again in INBOX where all my messages are marked as unread. - Do you know what can cause it and how can I avoid to happen again? - Is the used mdbox storage engine that fragile? Is the fault tolerance of other engines better? I have a backup from some days ago. Is it possible to somehow revert back to it and sync the new e-mails on top of those? Version: 2.4.2. Thank you, Ákos

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Configuration upgrade tool
by Aki Tuomi 15 Feb '26

15 Feb '26

Hi! To make migrating from Dovecot 2.3 to 2.4 a bit easier, we are now providing a tool that helps upgrade your existing configuration. The tool allows you to upload either a full dovecot.conf or selected ancillary configuration files from a 2.3 setup, and will attempt to convert them accordingly. You can find the tool here: https://dovecot.org/upgrader/ We do not store any of the configurations processed by the tool, nor do we track who uses it. It's offered as-is, without any warranty or guarantee. If you run into any issues, unexpected results, or have feedback about the tool, please let us know — it’s very much appreciated. Please note that the tool can make mistakes, so we strongly recommend carefully reviewing and testing the output before using it in production. There are currently no plans to release this tool as open source. Regards, Aki Tuomi Open-Xchange oy

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About mail_inbox_path and mail location
by Aki Tuomi 06 Feb '26

06 Feb '26

Hi! We've been noticing that many people are configuring mail_inbox_path. I assume that for most people this is because debian decided to include it in their default config, so that it would use /var/mail boxes for user INBOXes. If your inbox *does not* reside in some weird location, you should *not* set this setting to any value, instead you can either ensure it's commented out, or set to empty value. IN PARTICULAR, IT IS **NOT** REQUIRED SETTING. Setting it to some random weird value like '.' will just cause Problems, setting it to $MAIL_HOME/ or something else will just be either pointless or cause problems. Some most common conversions (please adjust to your environment) mail_home= /home/vmail/%u => mail_home = /home/vmail/%{user} mail_home = /home/vmail/%d/%u => mail_home = /home/vmail/%{user|domain}/%{user|username} or some variant of this. mail_location = maildir:~/ => mail_path = ~/ mail_driver = maildir mail_location = maildir:/var/srv/foo/%d/%u => mail_path = /var/srv/foo/%{user|domain}/%{user|username} mail_driver = maildir In addition you might want to convert INDEX=~/.index => mail_index_path=~/.index CONTROL=~/.control => mail_control_path=~/.control LAYOUT=fs => mailbox_list_layout=fs A minimal working config is mail_home=/home/vmail/%{user} mail_driver=maildir mail_path=~/maildir mail_uid=vmail mail_gid=vmail ## If you have settings like namespace other { location = maildir:/foo/bar } this converts into namespace other { mail_path = /foo/bar # optional, if this is matches your top level mail_driver = maildir } Hope this clears out some of the confusion. Aki

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Compiling Dovecot 2.4 on OpenBSD
by Joel Mawhorter 02 Feb '26

02 Feb '26

I'm writing to see if anyone has had success compiling Dovecot 2.4 on OpenBSD. I can't seem to find any documentation that lists prerequisites. At the moment, the 2.4.2 source tarball from the Dovecot site does not seem to compile on my OpenBSD 7.8 system and the error message is not very helpful. I'm unsure if this is just a problem of some required package not being installed. If anyone could point me to info to help move forward, I would appreciate that. Joel

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How can these MBOX files on a Dovecot-based IMAP server be converted to PST for access in Outlook?
by Rawnie Dolgato 31 Jan '26

31 Jan '26

MBOX files stored on a Dovecot-based IMAP server cannot be accessed directly in Microsoft Outlook, because Outlook does not support the MBOX file format. Outlook works with PST files, so a conversion step is mandatory. While it is technically possible to convert MBOX files to EML and then import them into Outlook, this approach is impractical for real-world scenarios. It is time-consuming, difficult to manage, and not suitable when handling bulk mailboxes or large datasets, which is typically the case with server-level backups. For this reason, an MBOX to PST conversion tool (such as BitRecover MBOX to PST Converter) is recommended. It supports bulk MBOX data, preserves folder structure and metadata, and allows selective migration based on criteria like date, sender, or subject. The process runs 100% offline, ensuring data security, and works on Windows, macOS, and Linux, making it suitable for both single and multi-mailbox migrations.

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