I've got 2 people on SmarterMail Version 14.1.5675 emailing each other.  In the Sent Items folder of the sender, the message shows as RTF format with the attached winmail.dat file.  Embedded in winmail.dat is a PDF test.  In the receiving mailbox, the message is displayed as HTML format without the attachment.  My guess is that SmarterMail is translating the RTF to HTML and dropping the attachment, but it's sort of hard to track that down in the logs.  Anyone see this before?

 

Example:

Sending end

------=_NextPart_000_0009_01D0E62B.8BD070E0
Content-Type: application/ms-tnef;
    name="winmail.dat"
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
    filename="winmail.dat"

 

Receiving end