[Dovecot] copy and empty userA folder1, append to /var/mail/userB

[Timo Sirainen]

On Wed, 2011-09-07 at 16:39 -0700, mathog wrote:
> Dovecot 2.0.13 on a 64 bit linux.
> 
> echo "" > ~me/mail/export
> 
> That worked fine on our last system, but dovecot doesn't like it.  It 
> leaves the imap indices for the
> export mailbox in an inconsistent state, so that roundcube (through 
> dovecot) refuses to drop
> messages into it.  The error message roundcube emits is:
> 
> ServerError:  Mailbox isn't a valid mbox file.

You change the "export" mbox to be one byte size containing LF. It
should instead be completely zero size. For example

echo -n > ~me/mail/export

Alternative could be to simply rm it?