[Dovecot] AppleMail causes dovecot error: file mbox-rewrite.c: line 429 assertion failed

I get the following error message in my syslog frequently when a user accesses the dovecot (IMAP) server from his OS X AppleMail client:

Nov 24 09:45:42 myhost imap(someuser): file mbox-rewrite.c: line 429 (mbox_write_header): assertion failed: (hdr_parsed_size.physical_size == hdr_size) Nov 24 09:45:42 myhost dovecot: child 23277 (imap) killed with signal 6

Usually each message appears 5-6 times.

The user on the other end doesn't notice any problems.

Any idea why this occurs and what I can do to prevent it?

I'm using dovecot from Debian sid, 0.99.11-3. Otherwise a fairly standard configuration.

Adam Rosi-Kessel http://adam.rosi-kessel.org