Mailbox is locked by POP server

Mirosław Jaworski mjaw at
Wed Dec 20 05:58:49 EST 2006

On Tue, 2006-12-19 at 21:21 -0500, Martin Schiøtz wrote:
> > > Personally I do not use POP3 any more - however I remember that there
> > > was a limitaition of 1 connection per mailbox in other servers.
> >
> > Yes.
> > The POP3 RFC states that operations such as DELEte a message will become
> > "final" after issuing a "QUIT" command. If connection breaks, no change is
> > made to the mailbox.
> >
> > For having multiple concurrent POP3 access to a mailbox a complete
> > transaction based model including rollbacks would be needed to implement
> > proper POP3. I don't think anybody wants to improve pop3d to accomplish
> > that ;-)
> >
> Personally I use IMAP and Thunderbird, but a lot of the users on this
> postfix/cyrus server use POP and Outlook. It looks like the problem
> occurs with Outlook clients using POP. At least I have seen the
> problem with Outlook 2002.

The problem has networking nature and does not depend on any MUA.

Connect to pop3 and leave it active, try to connect second time 
and you experience it.

In real life it happens when client connection brakes ( MUA dies,
someone pours coffe on his desktop, power dies and zillion 
other possible causes ).
Server keeps the connection until timeout ( surprised? ); if the
client connects again before timeout kicks in server sees incoming
connection as second and refuses it. 

No need to restart whole mail system; just wait for the timeout 
or remove that user's lock if you want to be polite. In old mbox
times one would simply remove /var/mail/<user>.lock file; in cyrus
one can kill manually pop3 process (not) handling hanging customer
and remove it's info in /var/imap/proc/<pid>


Miroslaw "Psyborg" Jaworski
GCS/IT d- s+:+ a C++$ UBI++++$ P+++$ L- E--- W++(+++)$ N++ o+ K- w-- O-
M- V- PS+ PE++ Y+ PGP t 5? X+ R++ !tv b++(+++) DI++ D+ G e* h++ r+++ y?

More information about the Info-cyrus mailing list