[Dovecot] Mailbox isn't a valid mbox file

[Kenneth Porter]

--On Wednesday, November 16, 2005 10:55 AM -0600 Cliff Hayes 
<chayes at afo.net> wrote:

> When I look in the file, I don't see anything unusual.  There's not much
> info on the Internet about this problem.  The only thing I found mentioned
> blank lines in the file.  So, I tested and found that I'm able to get mail
> on other accounts regardless of whether there are blank lines in between
> messages.

Generally the problem is that the file doesn't start with "From ". The 
"blank lines" are before these 5 characters. I've seen this issue come up 
periodically in one user's Mozilla Trash folder. Nothing writes to that 
folder except her IMAP client, and she runs only one instance. 
(dovecot-0.99.13-4.FC2) Each time, the problem has been a few thousand 
ASCII NUL's at the beginning of the file. I delete those and the system 
works fine for a few more weeks. At some point I'll update to the 1.0 
branch, which has different mbox code.