- dovecot - dovecot.org

Lazy-Expunge plugin documentation incomplete?
by Randolf Richardson 04 Sep '26

04 Sep '26

One of the Dovecot repository maintainers on GitHub recommended sending an eMail to you regarding the issue I encountered: Documentation for lazy-expunge doesn't work https://github.com/dovecot/documentation/issues/1555 -------- I converted from Dovecot 2.3 to Dovecot 2.4.1, which was not a minor upgrade. Anyway, I can't get the lazy-expunge plugin to work in 2.4.1 now. Here's my configuration file from 2.3 -- how can I get this working in 2.4.1? Thanks. namespace inbox { mailbox EXPUNGED { autoexpunge = 32days autoexpunge_max_mails = 100000 #auto = create } } # Namespace for lazy_expunge plugin namespace { prefix = EXPUNGED/ hidden = yes list = no subscriptions = no separator = / location = maildir:~/Maildir.deleted:INDEX= } mail_plugins = $mail_plugins lazy_expunge acl plugin { # Move expunged messages into the .EXPUNGED namespace lazy_expunge = EXPUNGED/ # Only move to expunged storage if this is the last copy of the message in the user´s account lazy_expunge_only_last_instance = yes # Exclude Drafts from lazy expunging lazy_expunge_exclude = \Drafts # Copy of each message is done with hard links whenever possible maildir_copy_with_hardlinks = yes # Define ACL so that user cannot list the .EXPUNGED mailbox # Example entry: .EXPUNGED owner rwstipekxa acl = vfile:/etc/dovecot/dovecot.acl # dovecot.acl contains one line: EXPUNGED owner ip # Expunged messages most likely don't want to be included in quota: quota_rule = EXPUNGED:ignore } #lazy_expunge_mailbox = EXPUNGED Here's an example of someone else who encountered the same problem: https://www.dovecot.org/mailman3/archives/list/dovecot@dovecot.org/thr ead/25BXSHQWGQQ3ACVZSYF3O3LC4WROTUCI/ Randolf Richardson, CNA - randolf(a)inter-corporate.com Inter-Corporate Computer & Network Services, Inc. Beautiful British Columbia, Canada https://www.inter-corporate.com/

2 4

Config parser bug?
by Pat Suwalski 03 Sep '26

03 Sep '26

Hello, I recently upgraded my servers from Debian Bullseye to Trixie (2.3 -> 2.4). I have a pretty basic config, though I use Maildir instead of Debian's default of mbox. In the process of getting things working correctly for the new config format, I believe I have stumbled on a bug. To make the inbox work correctly, I need the mail_inbox_path variable to be unset. This is because the default shipped 10-mail.conf file from Debian has: mail_driver = mbox mail_home = /home/%{user | username} mail_path = %{home}/mail mail_inbox_path = /var/mail/%{user} So, I overrode the mail_driver and mail_path in my local.conf. From the documentation, it seems like I should be able to set: mail_inbox_path = And that should clear it. Certainly, doveconf shows no mail_inbox_path variable set when that happens. However, no inbox! If I comment out mail_inbox_path from 10-mail.conf, doveconf output is identical, however the inbox works. My workaround is to make it the same as mail_path: mail_inbox_path = ~/Maildir However, I think the variable unsetting is buggy. This is dovecot 2.4.1. --Pat

3 10

discussion about "Remove doveadm_allowed_commands setting"
by Patrick Cernko 03 Sep '26

03 Sep '26

Hi Timo, hi list, I saw this commit (https://github.com/dovecot/core/commit/2b0947986ccb72e2f5ce13f8bd4b300e94e3…) on Dovecot's github repo: > doveadm: Remove doveadm_allowed_commands setting > The setting only compared the first command name against a list, which > gave a false sense of security. Anyone who is allowed to connect to the > doveadm server can already do practically anything with the commands > that were typically allowed: most commands take a -u/-A user parameter, > and commands like sync, backup and import take parameters that access > arbitrary paths. Restricting the command name doesn't change that, so > doveadm access must be given only to trusted clients regardless. I tried to understand the detailed reasoning but I don't get it. As far as I can follow the code not only the *first command name* is checked but every command send (in the list of commands via HTTP API). From our point of view, this setting has a clear security benefit like this: > # security: we only allow specific doveadm commands via doveadm-server and some more when coming from localhost > doveadm_allowed_commands = user,who > local 127.0.0.1/8 { > doveadm_allowed_commands = user,who,"sieve list","sieve get","sieve put","sieve activate" > } It limits the allowed commands in general to who and user which are read-only. Only if the connection is comming from localhost, we additionally grant some sieve commands for our web interface to manage and test sieve rulesets (https://gitlab.mpi-klsb.mpg.de/pcernko/sieveweb) All other commands are not allowed at all, e.g. it is not possible to delete mails or use dsync via the HTTP API. This policy matches our general security policy to only grant what's needed. So, Timo, I would like to ask, why this setting has to get removed (I assume in the next release) or if it can be restored again in the main branch? Is there anyone else using this setting besides me? What do the other users think about the removal of the setting? Best regards, -- Patrick Cernko <pcernko(a)mpi-klsb.mpg.de> +49 681 9325 5815 Joint Scientific IT and Technical Service Max-Planck-Institute für Informatik & Softwaresysteme

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Minor freebsd issue on dovecot 2.4.5
by Lucas Holt 02 Sep '26

02 Sep '26

On FreeBSD and MidnightBSD, Dovecot's net_getunixcred() relies on getpeereid(), which lacks PID info, causing every imap-login connection to register with anvil as pid=-1 and collide in its per-process hash. Here's an example fix for the problem. Note this was AI generated with claude fable and I don't know what your AI policy is. --- src/lib/net.c.orig 2026-08-28 00:00:00 UTC +++ src/lib/net.c @@ -9,6 +9,9 @@ #include <fcntl.h> #include <ctype.h> #include <sys/un.h> +#ifdef __FreeBSD__ +# include <sys/ucred.h> +#endif #include <netinet/tcp.h> #if defined(HAVE_UCRED_H) # include <ucred.h> /* for getpeerucred() */ @@ -832,6 +835,26 @@ cred_r->gid = ucred.unp_egid; cred_r->pid = ucred.unp_pid; return 0; +#elif defined(LOCAL_PEERCRED) && defined(__FreeBSD__) && __FreeBSD__ >= 13 + /* FreeBSD 13+ / MidnightBSD 4+ (getpeereid() exists too, but struct + xucred also carries the peer pid, which anvil needs) */ + struct xucred ucred; + socklen_t len = sizeof(ucred); + + if (getsockopt(fd, 0, LOCAL_PEERCRED, &ucred, &len) < 0) { + i_error("getsockopt(LOCAL_PEERCRED) failed: %m"); + return -1; + } + + if (ucred.cr_version != XUCRED_VERSION) { + errno = EINVAL; + return -1; + } + + cred_r->uid = ucred.cr_uid; + cred_r->gid = ucred.cr_gid; + cred_r->pid = ucred.cr_pid; + return 0; #elif defined(HAVE_GETPEEREID) /* OSX 10.4+, FreeBSD 4.6+, OpenBSD 3.0+, NetBSD 5.0+ */ if (getpeereid(fd, &cred_r->uid, &cred_r->gid) < 0) {

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Problem with setup of 2.4
by Doug Hardie 02 Sep '26

02 Sep '26

I have a production 2.3 server on the machine named "mail". I have installed 2.4 on the server named "test". I used the configuration converter to convert the production configuration to the new configuration structure. I did add a "log_debug = category=auth" line at the end for debug info. If I use the command to the production server: master# openssl s_client -connect 10.0.1.230:imap -starttls imap -quiet Connecting to 10.0.1.230 Can't use SSL_get_servername depth=3 C=US, O=Internet Security Research Group, CN=ISRG Root X2 verify return:1 depth=2 C=US, O=ISRG, CN=Root YE verify return:1 depth=1 C=US, O=Let's Encrypt, CN=YE2 verify return:1 depth=0 CN=mail.sermon-archive.info verify return:1 . OK Pre-login capabilities listed, post-login capabilities have more. At that point I can login and view mail. However, if i use the same command on the test server: master# openssl s_client -connect 10.0.1.235:993 -starttls imap Connecting to 10.0.1.235 CONNECTED(00000003) At this point is sits there accepting no input. The log shows: Aug 31 13:56:22 test dovecot[85915]: auth: Debug: conn unix:login (uid=144) [6]: Server accepted connection (fd=21) Aug 31 13:56:22 test dovecot[85915]: auth: Debug: conn unix:login (uid=144) [6]: auth client connected (pid=86045) There appears to be an SSL issue. The same certificates are used on both servers. Both servers are running FreeBSD 15.1. dovecot.conf is: test# cat dovecot.conf # Conversion performed at 2026-08-23 05:06:46.587238 dovecot_config_version = 2.4.2 dovecot_storage_version = 2.4.0 auth_mechanisms = plain cram-md5 auth_verbose_passwords = no base_dir = /var/run/home_mail/ first_valid_gid = 0 imap_capability = SASL-IR LOGIN-REFERRALS ID ENABLE LITERAL+ STARTTLS LOGINDISABLED AUTH=CRAM-MD5 lda_mailbox_autocreate = yes login_log_format_elements = user=<%{user}> method=%{mechanism} rip=%{remote_ip} lip=%{local_ip} mpid=%{mail_pid} %{secured} %{ssl_security} session=<%{session}> port=%{local_port} mail_driver = maildir mail_gid = 2222 mail_home = /var/mail/home_mail/%{user | username} mail_log_events = delete undelete expunge copy mailbox_delete mailbox_rename mail_log_fields = uid box msgid size from mail_log_prefix = %{protocol}(%{user})[%{remote_ip}]<%{session}>: mail_path = Maildir mail_temp_scan_interval = 0 mail_uid = 2222 postmaster_address = doug(a)sermon-archive.info protocols = imap syslog_facility = local1 verbose_proctitle = yes namespace inbox { inbox = yes mailbox Drafts { autoexpunge = 5 days special_use = \Drafts } mailbox Junk { autoexpunge = 5 days special_use = \Junk } mailbox Trash { autoexpunge = 50 days special_use = \Trash } mailbox Sent { autoexpunge = 30 days special_use = \Sent } mailbox "Sent Messages" { autoexpunge = 30 days special_use = \Sent } } passdb passwd-file { auth_username_format = %{user | username} default_password_scheme = CRYPT driver = passwd-file passwd_file_path = /usr/local/etc/dovecot/users } userdb static { driver = static fields { allow_all_users = yes home = /var/mail/home_mail/%d/%n } } service imap-login { inet_listener imap { port = 143 } inet_listener imaps { port = 993 ssl = yes } inet_listener imaps2 { port = 998 ssl = yes } } service auth { unix_listener auth-userdb { group = vmail mode = 0666 user = vmail } unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } } service stats { unix_listener stats-reader { group = vmail mode = 0660 user = vmail } unix_listener stats-writer { group = vmail mode = 0660 user = vmail } } ssl_server { cert_file = /www/certs/mail.pem dh_file = /usr/local/etc/dovecot/dh.pem key_file = # hidden, use -P to show it } protocol lda { mail_plugins { sieve = yes } } protocol imap { imap_metadata = yes mail_plugins { mail_log = yes notify = yes } } protocol pop3 { mail_plugins { mail_log = yes notify = yes } } #sieve_script personal { # active_path = /var/mail/home_mail/%{user | username}/.dovecot.sieve # driver = file # path = /var/mail/home_mail/%{user | username}/sieve #} mail_attribute { dict file { path = %{home}/Maildir/dovecot-attributes } } # Warnings during conversion: # - <memory>:8: dropping removed setting 'auth_stats' # - <memory>:50: mail_plugins uses $SET:mail_plugins but adds nothing # - <memory>:180: no converter for 'plugin/@1/stats_refresh' # - <memory>:181: no converter for 'plugin/@1/stats_track_cmds' # - pruned default: inbox prefix = '' log_debug = category=auth -- Doug

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Dovecot 2.4: shared mailboxes not working - maybe related to mail_path
by Markus Schönhaber 02 Sep '26

02 Sep '26

Hi, I've had a hard time trying to upgrade my dovecot 2.3 setup to v. 2.4 (debian 13, Dovecot installed from repo.dovecot.org) One thing I still haven't got to work is mailbox sharing. I have configured this (full doveconf -n output attached): mail_driver = mdbox mail_home = /var/spool/vmail/home/%{user | domain}/%{user | username} mail_path = /var/spool/vmail/mail/%{user | domain}/%{user | username} mail_plugins = quota acl namespace inbox { inbox = yes separator = / } namespace shared { mail_home = /var/spool/vmail/home/%{owner_domain}/%{owner_username} list = children prefix = shared/$domain/$username/ separator = / subscriptions = no type = shared } acl_driver = vfile mail_plugins { acl = yes } protocol imap { mail_plugins { imap_acl = yes } } acl_sharing_map { dict file { path = /var/spool/vmail/home/shared-mailboxes } } Now, given two users: 1: sharing-user(a)example.com 2: sharing-client(a)example.net User 1 wants to share his mailbox "4you" to user 2 by setting these acls: > # doveadm acl add -u sharing-user(a)example.com 4you user=sharing-client(a)example.net lookup read write-seen But the shared mailbox isn't visible for user 2 (in fact, not even the namespace is, since list = children). acl debug shows this: > # doveadm acl debug -u sharing-client(a)example.net shared/example.com/sharing-user/4you > doveadm(sharing-client(a)example.net): Error: Mailbox shared/example.com/sharing-user/4you: Mailbox '4you' in namespace shared doesn't exist in /var/spool/vmail/mail/example.net/sharing-client/mailboxes/4you/dbox-Mails So the shared mailbox is looked for in user 2's mail_path, not in user 1's, who shares it and where the mailbox actually resides. So, I tried and set mail_path = /var/spool/vmail/path/%{owner_domain}/%{owner_username} for the shared namespace. This does not only seem reasonable but also is mentioned in the second config example here: https://doc.dovecot.org/2.4.4/core/config/shared_mailboxes.html#user-shared… But that doesn't help. Instead I get: > # doveadm acl debug -u sharing-client(a)example.net shared/example.com/sharing-user/4you > doveadm(sharing-client(a)example.net): Error: Namespace shared: mail_storage settings: Failed to parse configuration: Failed to expand mail_path setting variables: Unknown variable 'owner_domain' > doveadm(sharing-client(a)example.net): Error: Namespace shared: mail_storage settings: Failed to parse configuration: Failed to expand mail_path setting variables: Unknown variable 'owner_domain' > doveadm(sharing-client(a)example.net): Error: Namespace shared: mail_storage settings: Failed to parse configuration: Failed to expand mail_path setting variables: Unknown variable 'owner_domain' > doveadm(sharing-client(a)example.net): Error: Mailbox shared/example.com/sharing-user/4you: Can't open mailbox shared/example.com/sharing-user/4you: Internal error occurred. Refer to server log for more information. [2026-08-20 14:53:40] Swapping %{owner_domain} and %{owner_username} in the config above, I get Unknown variable 'owner_username' as error. If I set mail_path = /var/spool/vmail/mail/example.com/sharing-user i. e. I hard-code the sharing user's mail_path, sharing works for this particular user. But that won't help if a second user wants to share mailboxes too. > # doveadm acl debug -u sharing-client(a)example.net shared/example.com/sharing-user/4you > doveadm(sharing-client(a)example.net): Info: Mailbox shared/example.com/sharing-user/4you: Mailbox '4you' is in namespace shared > doveadm(sharing-client(a)example.net): Info: Mailbox shared/example.com/sharing-user/4you: Mailbox path: /var/spool/vmail/mail/example.com/sharing-user/mailboxes/4you/dbox-Mails > doveadm(sharing-client(a)example.net): Info: Mailbox shared/example.com/sharing-user/4you: All message flags are shared across users in mailbox > doveadm(sharing-client(a)example.net): Info: Mailbox shared/example.com/sharing-user/4you: User sharing-client(a)example.net has rights: lookup read write-seen > doveadm(sharing-client(a)example.net): Info: Mailbox shared/example.com/sharing-user/4you: Mailbox found from dovecot-acl-list > doveadm(sharing-client(a)example.net): Info: Mailbox shared/example.com/sharing-user/4you: User sharing-user(a)example.com found from ACL shared dict > doveadm(sharing-client(a)example.net): Info: Mailbox shared/example.com/sharing-user/4you: Mailbox shared/example.com/sharing-user/4you is visible in LIST What am I doing wrong? How to do ist right? -- Regards mks

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Problem with setup of 2.4
by Doug Hardie 01 Sep '26

01 Sep '26

I have a production 2.3 server on the machine named "mail". I have installed 2.4 on the server named "test". I used the configuration converter to convert the production configuration to the new configuration structure. I did add a "log_debug = category=auth" line at the end for debug info. If I use the command to the production server: master# openssl s_client -connect 10.0.1.230:imap -starttls imap -quiet Connecting to 10.0.1.230 Can't use SSL_get_servername depth=3 C=US, O=Internet Security Research Group, CN=ISRG Root X2 verify return:1 depth=2 C=US, O=ISRG, CN=Root YE verify return:1 depth=1 C=US, O=Let's Encrypt, CN=YE2 verify return:1 depth=0 CN=mail.sermon-archive.info verify return:1 . OK Pre-login capabilities listed, post-login capabilities have more. At that point I can login and view mail. However, if i use the same command on the test server: master# openssl s_client -connect 10.0.1.235:993 -starttls imap Connecting to 10.0.1.235 CONNECTED(00000003) At this point is sits there accepting no input. The log shows: Aug 31 13:56:22 test dovecot[85915]: auth: Debug: conn unix:login (uid=144) [6]: Server accepted connection (fd=21) Aug 31 13:56:22 test dovecot[85915]: auth: Debug: conn unix:login (uid=144) [6]: auth client connected (pid=86045) There appears to be an SSL issue. The same certificates are used on both servers. Both servers are running FreeBSD 15.1. dovecot.conf is: test# cat dovecot.conf # Conversion performed at 2026-08-23 05:06:46.587238 dovecot_config_version = 2.4.2 dovecot_storage_version = 2.4.0 auth_mechanisms = plain cram-md5 auth_verbose_passwords = no base_dir = /var/run/home_mail/ first_valid_gid = 0 imap_capability = SASL-IR LOGIN-REFERRALS ID ENABLE LITERAL+ STARTTLS LOGINDISABLED AUTH=CRAM-MD5 lda_mailbox_autocreate = yes login_log_format_elements = user=<%{user}> method=%{mechanism} rip=%{remote_ip} lip=%{local_ip} mpid=%{mail_pid} %{secured} %{ssl_security} session=<%{session}> port=%{local_port} mail_driver = maildir mail_gid = 2222 mail_home = /var/mail/home_mail/%{user | username} mail_log_events = delete undelete expunge copy mailbox_delete mailbox_rename mail_log_fields = uid box msgid size from mail_log_prefix = %{protocol}(%{user})[%{remote_ip}]<%{session}>: mail_path = Maildir mail_temp_scan_interval = 0 mail_uid = 2222 postmaster_address = doug(a)sermon-archive.info protocols = imap syslog_facility = local1 verbose_proctitle = yes namespace inbox { inbox = yes mailbox Drafts { autoexpunge = 5 days special_use = \Drafts } mailbox Junk { autoexpunge = 5 days special_use = \Junk } mailbox Trash { autoexpunge = 50 days special_use = \Trash } mailbox Sent { autoexpunge = 30 days special_use = \Sent } mailbox "Sent Messages" { autoexpunge = 30 days special_use = \Sent } } passdb passwd-file { auth_username_format = %{user | username} default_password_scheme = CRYPT driver = passwd-file passwd_file_path = /usr/local/etc/dovecot/users } userdb static { driver = static fields { allow_all_users = yes home = /var/mail/home_mail/%d/%n } } service imap-login { inet_listener imap { port = 143 } inet_listener imaps { port = 993 ssl = yes } inet_listener imaps2 { port = 998 ssl = yes } } service auth { unix_listener auth-userdb { group = vmail mode = 0666 user = vmail } unix_listener /var/spool/postfix/private/auth { group = postfix mode = 0660 user = postfix } } service stats { unix_listener stats-reader { group = vmail mode = 0660 user = vmail } unix_listener stats-writer { group = vmail mode = 0660 user = vmail } } ssl_server { cert_file = /www/certs/mail.pem dh_file = /usr/local/etc/dovecot/dh.pem key_file = # hidden, use -P to show it } protocol lda { mail_plugins { sieve = yes } } protocol imap { imap_metadata = yes mail_plugins { mail_log = yes notify = yes } } protocol pop3 { mail_plugins { mail_log = yes notify = yes } } #sieve_script personal { # active_path = /var/mail/home_mail/%{user | username}/.dovecot.sieve # driver = file # path = /var/mail/home_mail/%{user | username}/sieve #} mail_attribute { dict file { path = %{home}/Maildir/dovecot-attributes } } # Warnings during conversion: # - <memory>:8: dropping removed setting 'auth_stats' # - <memory>:50: mail_plugins uses $SET:mail_plugins but adds nothing # - <memory>:180: no converter for 'plugin/@1/stats_refresh' # - <memory>:181: no converter for 'plugin/@1/stats_track_cmds' # - pruned default: inbox prefix = '' log_debug = category=auth -- Doug -- Doug

1 0

global ACL file with Dovecot >=2.4.3
by Markus Schönhaber 31 Aug '26

31 Aug '26

Hi, https://doc.dovecot.org/2.4.5/core/plugins/acl.html#acl_global_path says that the acl_global_path config setting was removed with Dovecot 2.4.3 and one should use acl instead. But it does not explain how the new config setting should look like. The documentation further down on the page didn't help me to get the idea. While here https://doc.dovecot.org/2.4.5/core/plugins/acl.html#global-acl-file it is said that the > Global ACL file path is specified as a parameter to vfile driver in > |acl > <https://doc.dovecot.org/2.4.5/core/summaries/settings.html#acl>|, > |/etc/dovecot/dovecot-acl| in the above example. I don't see what the "above example" exactly refers to. In fact, the string "|/etc/dovecot/dovecot-acl" doesn't appear a second time on this page. Can someone give an example, how to configure a global ACL file for Dovecot >=2.4.3? -- Regards mks |

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Dovecot 2.4.1 on DietPi/ARM64: Cannot move/delete any folders via IMAP, and three specific folders are unreadable (but other folders work)
by rdorau＠gmx.de 31 Aug '26

31 Aug '26

Hello, I'm running Dovecot 2.4.1 on a Raspberry Pi 4 with DietPi (Debian 13, ARM64) and had to migrate from another OS with Dovecot 2.3. My maildir is at /var/mail/mailuser. It contains many dot‑prefixed subfolders, e.g. .Archiv, .Archiv.Reisen, .Sozio. Relevant parts from doveconf -n: text dovecot_config_version = 2.4.0 auth_mechanisms = plain login dovecot_storage_version = 2.4.0 listen = * login_trusted_networks = 192.168.178.0/24 mail_driver = maildir mail_home = /var/mail/%u mail_path = /var/mail/%u protocols = imap ssl = no passdb pam { driver = pam } userdb passwd { driver = passwd } namespace inbox { inbox = yes prefix = separator = . } Problem 1: Cannot move, delete, or rename any folder via IMAP. In Thunderbird, I can move individual messages between folders, but I cannot move, rename, or delete any folder itself. This affects all folders, not just specific ones. Right‑clicking a folder and choosing “Delete”, “Rename”, or dragging a folder to another location does nothing – no error, just no effect. I have checked permissions on the maildir; mailuser owns the directories and files, and dovecot is in the mailuser group. Problem 2: Three specific folders cannot be opened (message body not loaded). Most of my archive works fine. But exactly these three folders fail: .Archiv.merk.Versicherungen.Axa (Reiserücktritt) .Archiv.merk.Versicherungen.Bavaria_Haftpflicht .Archiv.merk.Versicherungen.LVM_Auslandsreisekrankenversicherung In Thunderbird, I see the message headers, but when I try to open a message, the body stays empty. On the server, the files are intact – head shows the full header, and the messages are readable as plain files. Other folders with similar special characters (e.g. &APw-, &AOQ-, &ANY-) work without problems. So I don't think the special characters are the cause. Problem 3: doveadm mailbox list shows only INBOX and Trash. Even though the maildir contains many dot‑prefixed subfolders, doveadm mailbox list -u mailuser returns only: text Trash INBOX In Thunderbird, the subfolders appear inside INBOX (e.g. INBOX.Archiv, INBOX.Archiv.Reisen), which is basically correct. But doveadm does not list them as separate mailboxes. What I have already tried (without success): Renaming the three problematic folders to simple names (e.g. Axa_Reiseruecktritt) and creating new folders with the copied mails. Deleting Dovecot index files (dovecot.index*, dovecot-uidlist, subscriptions) and restarting Dovecot. Changing namespace separator and prefix settings. Adding dovecot to mailuser group and adjusting permissions (chmod 750). Forcing Thunderbird to re‑synchronize by deleting local .msf files – after that, the three folders sometimes disappear or become empty in Thunderbird, but the mail files remain on disk. None of this made doveadm mailbox list show the subfolders, and the three folders remain unreadable. My questions: Why does doveadm mailbox list not show the subfolders, even though they exist as dot‑prefixed directories and Thunderbird displays them? What do I need to change so that Dovecot lists them properly? Why can I not move, delete, or rename any folder via IMAP, even though moving messages works? Is this a configuration issue (e.g. missing ACL, wrong permissions, or something with the namespace)? How can I make the three unreadable folders readable again? What is the safest way to rebuild their indexes or re‑create them so that Thunderbird can open the messages? If the folder names are problematic (e.g., due to length or special characters), what is the correct way to rename them in the maildir structure so that Dovecot and Thunderbird can handle them normally? I need a method that preserves the existing mails and the folder hierarchy. I would be very grateful for any hints, because I'm stuck and have already spent many hours on this. Thank you in advance.

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NFC normalization rename errors after 2.3 to 2.4 upgrade (mdbox)
by Jan Münnich 29 Aug '26

29 Aug '26

Hi, We just upgraded from 2.3 to 2.4.3 and are now getting errors like this for any mailbox with German umlauts in the name: "Error: Failed to rename mailbox 'Anträge' for NFC normalization: Mailbox doesn't exist: Anträge" The mailboxes work fine otherwise, doveadm mailbox status shows them with correct message counts. The errors show up on IMAP access but don't seem to break anything. We're using mdbox. On disk the directory is stored as mUTF-7: Antr&AOQ-ge doveadm mailbox list gives back the name with c3 a4 for the ä, which is already NFC. We double-checked with python3 unicodedata and it confirms the name is NFC. So it seems like dovecot is trying to rename something that doesn't need renaming, and then failing. Is there a way to turn off this automatic rename? Or is this a known issue with mdbox and mUTF-7 directory names? Any help would be appreciated to find out if this is a bug or a configuration issue on our side! Thanks, Jan

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