Incoming e-mails start with -->

The setup in question is a Hetzner root server, running IPSConfig 2 on Debian Lenny.
When any of my accounts receives an e-mail, it always starts with --> in the message.

Any idea what the reason could be?

 

Is MailScan enabled for these email accounts (in ISPConfig)?

 

Yes it is.

 

Disable it and see if that changes anything.

 

Now that I've turned Mailscan off, it stopped putting --> in the mail.
So now that we've established it's Mailscan that's doing it... How do I go about fixing it?

 

I'm finding this interesting. Sorry I can't contribute anything yet!

 

I can't say why it's behaving like that. I suggest you leave Mailscan off.

 

I'm almost sure I saw this somewhere else and an explanation on how to fix it. But I can't remember where, for the life of me.