Thank you Duncan for the info about the patch. I would try it, but I'm sure it would not be accepted by the tech stuff as it is not official. As I said in another thread, this is what happens when autocreate is ON in a murder setup with several backends, and a user accesses a shared mailbox residing on a different server. This is an excerpt of backend1 maillog: canonified backend1 -> backend1 mupdate NO response: mailbox already exists MUPDATE: can't reserve mailbox entry for 'example.com!user.onBE2' autocreateinbox: User onBE2@xxxxxxxxxxx, INBOX failed. unable to reserve mailbox on mupdate server seen_db: user onBE2@xxxxxxxxxxx opened /var/lib/imap/domain/e/example.com/user/z/onBE2.seen open: user onBE2@xxxxxxxxxxx opened user/onBE1/778899 In words, the backend not owning the mailbox tries to create it, but receives a deny from the murder server. Then it opens the target mailbox (onBE1/778899) and creates the .seen structure. So far this means a messy maillog file. I will use autocreate just to populate my backends from the backend itself (with some imtest iteration, or whatever) and then switch it off. Looking forward to a MUPDATE protocol update or cyrus official patch. Paolo ---- Cyrus Home Page: http://cyrusimap.web.cmu.edu/ Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html