Besides the main.cf entry it should be checked whether the
/etc/postfix/master.cf definition of the cyrus transport is proper:

cyrus     unix  -       n       n       -       -       pipe
  user=cyrus argv=/cyrus/bin/deliver -e -r ${sender} -m ${extension}
${user}

To where is that path pointing, a chroot? Sorry, as being a Sendmail
user I lack some important knowledge about Postfix.

The only change I remember being necessary for master.cf is to correct
the path "/cyrus/bin/deliver" to "/usr/lib/cyrus-imapd/deliver" -- the
"/cyrus/bin" stuff is just Wietse's notation for "wherever the cyrus
binaries happen to be on your system"

The old-cyrus transport line should perhaps be commented out to avoid
confusion as well...

/usr/share/doc/postfix-mumble/README_FILES/LMTP_README already covers
all the ways of connecting Postfix and Cyrus using LMTP....

fc3test2's postfix-2.1.4-1.src.rpm's master.cf still refers to
/cyrus/bin/deliver, even though the cyrus-imapd package puts it in
/usr/lib/cyrus-imapd/deliver

Wietse can't know it in general, but we know where it is placed, and
the packages should be configured to work with each other out-of-the-box. 

*** Bug 145277 has been marked as a duplicate of this bug. ***

With respect to comment #1, the correct parameter is:

mailbox_transport = lmtp:unix:/var/lib/imap/socket/lmtp

Note, files are installed in /var/lib/imap now instead of /var/imap.

With respect to comments #2 and #3,
/usr/lib/cyrus-imapd/deliver
is the correct path for our installation.

With respect to postfix/cyrus-imapd configuration. Although the
"deliver" mechanism should still work my understanding is that it is
deprecated in favor of lmtp since both postfix and cyrus now support
it. Whenever I test the postfix/cyrus compbination I use lmtp, not
"deliver". Perhaps we should remove references to "cyrus" in main.cf
and "deliver" in master.cf as an encouragement to use the lmtp
mechanism and to simplify things.

Here is my suggest

# If using the cyrus-imapd IMAP server deliver local mail to the IMAP
# sever using LMTP (Local Mail Transport Protocol), this is prefered
# over the older cyrus deliver program by setting the
# mailbox_transport as below:
#
# mailbox_transport = lmtp:unix:/var/lib/imap/socket/lmtp
#
# The efficiency of LMTP delivery for cyrus-imapd can be enhanced via
# these settings.
#
# local_destination_recipient_limit = 300
# local_destination_concurrency_limit = 5
#
# Of course you should adjust these settings as appropriate for the
# capacity of the hardware you are using. The recipient limit setting
# can be used to take advantage of the single instance message store
# capability of Cyrus. The concurrency limit can be used to control
# how many simultaneous LMTP sessions will be permitted to the Cyrus
# message store. 


This bug was just assigned to me as the owner of cyrus-imapd, but the
changes belong in the postfix rpm. If there is agreement that my
suggestions are appropriate then I think the postfix maintainer
(Thomas?) should do the rpm editing so we don't step on each others
toes in the various CVS branches.

BTW, the postfix LMTP readment file seems to have disappeared, its not
in the distribution any more (technically it there, but the contents
say the info in on the web site), but on the postfix doc page cyrus
was empty, LMTP, was empty, and it was not discussed in the general
configuration pages (maybe I missed it?).

John,
your suggestion about the comment on how using the LMTP mail transport
between Postfix and Cyrus-IMAPd sounds reasonable to me as it is then
simple to adjust the setup.
And yes, the Postfix maintainer - is it Thomas Wörner? - should be
notified. (The RFE bugzilla entry was made for the Postfix package by me.)

Fixed in rawhide in package postfix-2.2.5-2.1 or newer.