[Dovecot] Urgent problem: Dovecot fetches the same mails multiple times per POP

[Andi Meier]

I have a problem since a couple of hours:
I manage several mboxes on a virtual server using Dovecot (over POP3).

Until a few hours ago, it worked well, but since 11:50, the e-mail clients which access Dovecot's mailboxes, receive all e-mails new each 
time the mailbox is queried.

For example:
15:40 fetches 22 new mails
15:41 fetches the same 22 mails again as new
15:42 fetches the same 22 mails again as new
etc.


Dovecot version is 1.0.15 on Debian Lenny.

How can I fix this? How can I diagnose what's wrong? The mailbox files themselves seem ok, no dupe messages.

I noticed that in the /var/log/mail.log Dovecot says:

------- START ---------
Jan 10 15:27:08 lvps87-230-81-99 dovecot: POP3(office): Disconnected: Logged out top=0/0, retr=23/6273313, del=23/23, size=6272894
Jan 10 15:40:02 lvps87-230-81-99 dovecot: POP3(office): Effective uid=1002, gid=1002
Jan 10 15:40:02 lvps87-230-81-99 dovecot: POP3(office): mbox: data=/var/mail:INBOX=/var/mail/office
Jan 10 15:40:02 lvps87-230-81-99 dovecot: POP3(office): mbox: root=/var/mail, index=/var/mail, inbox=/var/mail/office
Jan 10 15:40:02 lvps87-230-81-99 dovecot: POP3(office): mbox sync: Expunged message reappeared in mailbox /var/mail/office (UID 3234 < 3261, 
seq=2, idx_msgs=0)
Jan 10 15:40:02 lvps87-230-81-99 dovecot: pop3-login: Login: user=<office>, method=PLAIN, rip=80.122.113.70, lip=87.230.81.99
Jan 10 15:40:02 lvps87-230-81-99 dovecot: POP3(office): mbox sync: UID inserted in the middle of mailbox /var/mail/office (3261 > 3234, 
seq=2, idx_msgs=24)
Jan 10 15:40:02 lvps87-230-81-99 dovecot: POP3(office): mbox sync: UID inserted in the middle of mailbox /var/mail/office (3285 > 3234, 
seq=2, idx_msgs=24)
Jan 10 15:40:22 lvps87-230-81-99 dovecot: POP3(office): mbox sync: UID inserted in the middle of mailbox /var/mail/office (3309 > 3234, 
seq=2, idx_msgs=24)
Jan 10 15:40:22 lvps87-230-81-99 dovecot: POP3(office): Disconnected: Logged out top=2/0, retr=24/6274745, del=24/24, size=6274309
------- END ---------

What puzzles me: Each time the retr=XX value is never decreasing. Shouldn't it be 0/xxxxx the next time when the mails are not kept on the 
server? Apparently Dovecot does not manage to remove the mails form the mbox, although the email client tells it so (=> del=24/24)
Is this the problem? How can I check this?


I am very thankful for any hints!

Cheers,
Andi