[Dovecot] Problem copying e-mails to IMAP - Dovecot 2.1.2

[Timo Sirainen]

On Fri, 2012-03-16 at 13:51 +0300, Odhiambo Washington wrote:
> I have a situation where I need to migrate e-mails from Outlook 2011 (Mac)
> to Apple Mail. Having looked at all options, I have resorted to the,
> perhaps, most difficult way: Create folders on the IMAP server, copy
> e-mails into them from Outlook, connect Apple Mail and do the reverse.
> However, I have hit a wall.
> 
> I am running Dovecot 2.1.2 on FreeBSD, with mdbox storage.
> 
> In my first attempt, I have 1792 messages in the "Sent Items" folder for
> Outlook. I have tried (3 times) to copy the messages to the IMAP/Sent Items
> folder, but the process dies at some point. When that happens, Outlook pops
> a screen saying "IMAP session state is inconsistent, please relogin".
..
> Mar 16 13:33:23 jaribu dovecot: imap(wash at kictanet.or.ke): Error: Corrupted
> dbox file /var/spool/virtual/kictanet.or.ke/wash/mdbox/storage/m.4 (around
> offset=894): msg header has bad magic value

Well, this isn't good. The mdbox was empty when you first started
copying the mails? This is a normal local FreeBSD filesystem (not NFS or
something else weird)?

What happens if you now run:

doveadm force-resync -u wash at kictanet.or.ke INBOX

Does it show any errors? If not, and if you try to copy the mails again,
does it still fail?

It's interesting if you can reproduce this. I wonder if it's because of
FreeBSD or if it's related to single instance storage.