Florin Portase writes:

type of error: COREDUMP Feb 04 11:49:59 imap(portase.florin@medianetork.ro): Fatal: master: service(imap): child 23391 killed with signal 11 (core dumped)

Disabling of shared mailbox results in correct functioning of dovecot. To mention again: dovecot version previous to 2.2 was working OK.

Debugging of this sort usually requires submitting a core dump traceback

http://dovecot.org/bugreport.html

This might be a known issue (check the Dovecot archives).

Joseph Tam <jtam.home@gmail.com>