Mine has always behaved like this.
It looks up the root user in the auth database from the dovecot
config, and attemps to change to that user, and in this type of case
that would be vmail.
Then it attempts to check the mail_home and kind of fails, unless you
give vmail permission to that path that would be created using the
root user.
Quoting Thomas Harold <thomas-lists at nybeta.com>:
> On 8/2/2011 8:45 AM, Stephan Bosch wrote:
>>
>> What versions of Dovecot (obviously v2.0+) and Pigeonhole are you using
>> and what is your config (show dovecot -n output) ?
>>
>> I suspect there may be a bug.
>>
>
> dovecot-2.0-pigeonhole-0.2.3 - downloaded and compiled from source
> this week. The dovecot package itself comes from ATRPMs and is
> 2.0.13.
>
> Name : dovecot
> Arch : x86_64
> Epoch : 1
> Version : 2.0.13
> Release : 1_129.el5
> Size : 5.1 M
> Repo : installed
> Summary : Dovecot Secure imap server
> URL : http://www.dovecot.org/
> License : MIT
>
> Name : dovecot-devel
> Arch : x86_64
> Epoch : 1
> Version : 2.0.13
> Release : 1_129.el5
> Size : 667 k
> Repo : installed
> Summary : Libraries and headers for Dovecot
> URL : http://www.dovecot.org/
> License : MIT
>
> Output of dovecot -n
>
> # 2.0.13: /etc/dovecot/dovecot.conf
> # OS: Linux 2.6.18-274.el5 x86_64 Red Hat Enterprise Linux Server
> release 5.7 (Tikanga)
> auth_verbose_passwords = sha1
> lda_mailbox_autocreate = yes
> lda_mailbox_autosubscribe = yes
> listen = 127.0.0.1, 1.2.3.4
> mail_gid = vmail
> mail_home = /var/vmail/%d/%n
> mail_location = maildir:~/Maildir
> mail_uid = vmail
> managesieve_notify_capability = mailto
> managesieve_sieve_capability = fileinto reject envelope
> encoded-character vacation subaddress comparator-i;ascii-numeric
> relational regex imap4flags copy include variables body enotify
> environment mailbox date
> mbox_write_locks = fcntl
> passdb {
> args = /etc/dovecot/conf.d/dovecot-sql.conf.ext
> driver = sql
> }
> plugin {
> sieve = ~/.dovecot.sieve
> sieve_after = /etc/dovecot/sieve/after/
> sieve_before = /etc/dovecot/sieve/before/
> sieve_dir = ~/sieve
> sieve_global_dir = /etc/dovecot/sieve/globalinclude/
> }
> protocols = imap pop3 lmtp sieve
> service auth {
> unix_listener /var/spool/postfix/private/auth {
> mode = 0666
> }
> unix_listener auth-userdb {
> group = vmail
> user = vmail
> }
> }
> service imap-login {
> process_min_avail = 5
> }
> service pop3-login {
> inet_listener pop3 {
> address = 1.2.3.4
> }
> inet_listener pop3s {
> address = 1.2.3.4
> }
> }
> ssl = required
> ssl_cert = </etc/pki/tls/private/certs/example_com.crt
> ssl_key = </etc/pki/tls/private/example_com.key
> protocol lda {
> log_path = /var/log/dovecot/dovecot-lda
> mail_plugins = " sieve"
> }