[Dovecot] Mbox corruption - Inbox beginning with 'FFrom' or 'FrFrom'

[Timo Sirainen]

On Fri, 2010-05-07 at 15:03 -0400, Erik Kratzenberg wrote:
> >>>>      -Dovecot.log : Mar 29 11:00:06 Error: POP3(user_login):
> >>   >  >         Couldn't init INBOX: Mailbox isn't a valid mbox
> >>   >  >      -The mailbox start with either 'FFrom or 'FrFrom'
> It's happening several times a day, sometimes to the same mailbox.

How often does the same user get the error?

> We also noticed some other storage and assertion errors around the same 
> time the corruption occurs which may or may not be related:
> 
> Mar 26 14:49:36 dovecot: Panic: POP3(user at home.com):
> file mbox-sync.c: line 1314 (mbox_sync_handle_eof_updates): assertion
> failed: (offset == 0|| offset > 31)

There's a good chance this is related.

> Mar 24 15:21:59 dovecot: POP3(user at home.com): Cached
> message offset 2 is invalid for mbox file
> /usr/boxes/mailbox

Are you using filesystem quota for users? That might explain this.
Otherwise, the above shouldn't be happening if Dovecot is the only
software writing to the mbox files..

> I'm not sure if "mail_debug=yes" will give us any additional info, but 
> I'm turning that on now.

No, that won't log anything useful.