Sending RTF with Attachment as MIME Loses Attachment

When you send a message with a MIME attachment from an Exchange client and have configured an Internet recipient to "Always send to this recipient as RTF", and that recipient uses a POP3 client, the recipient will not receive the attachment.

The MIME-encoded attachment is still present but is not accessible by the POP3 client (depending on the receiving client). This problem only happens when sending an attachment as MIME.

There are two ways to work around this problem:

1. Disable the option "Always send to this recipient as RTF" when sending an attachment to an Internet recipient using a POP3 client.
2. Do not include an attachment in an RTF message.

Microsoft has confirmed this to be a problem in Microsoft Exchange Server 5.5. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

Most POP3 clients do not understand Rich Text Format (RTF) used by Microsoft transport-neutral encapsulation format (TNEF). Consequently, the sender must turn off the option "Always send to this recipient as RTF", in order for the POP3 client to see the attachments.