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

[Timo Sirainen]

On Tue, 2010-07-27 at 09:32 -0400, Erik Kratzenberg wrote:
> > If you delete all messages from mailbox, INTERNAL DATA message doesn't
> > show up there? The mbox file size becomes zero? If so, it doesn't sound
> > like you're really using Dovecot v1.x..
> 
> It looks like if I'm starting without the folder existing (whether it's 
> a new delivery rule or you delete the folder from IMAP), deliver doesn't 
> create the FOLDER INTERNAL DATA so it will just start appending messages 
> to it.

Right, that's how it should work.

> Once that first message is received, IMAP won't create the FOLDER 
> INTERNAL DATA message until I delete all the messages from the folder.

Same here.

> When I delete all the messages from the folder, they are not actuall 
> removed until I restart my mail client.  If new messages are received to 
> that folder before I restart my mail client, then it also won't create 
> the FOLDER INTERNAL DATA message.

I guess this means the messages are marked as \Deleted, but client
hasn't sent EXPUNGE yet.

> I'm not sure if that's directly related to this issue, but I know the 
> corrupted From line is always the first message in a mailbox and is 
> never the FOLDER INTERNAL DATA message.

What I find strange is that you said this happens to POP3 users who
delete all of the mails. Once all mails are deleted, the FOLDER INTERNAL
DATA message should be written. After it is written, it should never get
deleted afterwards. So how is it possible that POP3 users who regularly
delete all of their mails still don't have the FOLDER INTERNAL DATA
message?