Version:           1.6 (using KDE 3.2.0 RC1, compiled sources)
Compiler:          gcc version 3.2.2 20030222 (Red Hat Linux 3.2.2-5)
OS:          Linux (i686) release 2.4.20-18.9

Forwarding some email, sent by Microsoft MUAs, the attachement is removed. I'm not sure, what causes this, but my best guess is that the attachement is not included if the sender did not specify any text, but only sent the attachement and therefore the Mail is not a MIME/Multipart Mail.

One Example of a Mail of which the attachment is not forwarded:

-----------SNIP-------------
Received: from XXXXXXXXXXXXX ([XXXXXXXXXXXXX]) by XXXXXXXXXXXXX with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2657.72)
	id D763Y4ZQ; Fri, 30 Jan 2004 13:34:49 +0100
X-Authentication-Warning: XXXXXXXXXXXXXXXXXXXX: major set sender to XXXXXXXXXXXXXXXXXXXXXXX using -f
Message-ID: <F3123864FB69D411946000D0B77FBBDF08380DE9@XXXXXXXXXXXX>
From: XXXXXXXXXXXXXXXXXXXXXXXX
To: XXXXXXXXXXXXXXXXX
Subject: [fun]
Date: Fri, 30 Jan 2004 13:33:14 +0100
MIME-Version: 1.0
X-Mailer: Internet Mail Service (5.5.2657.72)
Content-Type: video/mpeg;
  name="186W1.mpeg"
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
	filename="186W1.mpeg"
Sender: XXXXXXXXXXXXXXXXXXXXX
Precedence: bulk
Reply-To: XXXXXXXXXXXXXXXXXXXXXXXXXXX
X-UID: 36510
Status: RO
X-Status: R
X-KMail-EncryptionState: N
X-KMail-SignatureState: N
X-KMail-MDN-Sent:  

AAABuiEAAQATgAzPAAABuwAMgAzPBuH/4OAlwMAgAAABvgfcD///////////////////////////
////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////
[....binary data continues]
-----------SNIP-------------

Another Email, which is of the MIME type multipart/mixed that contains a text/plain and a binary content is forwarded correctly.