SMTP Messages with TNEF Sent Via the Internet Mail Service May Lose Formatting and Attachments

When you receive SMTP messages with TNEF via the Internet Mail Service, message formatting and attachments may be lost.

This problem only occurs when the X-MS-TNEF-CORRELATOR section of the SMTP message header is wrapped onto a second line. The following an example from a message:

If the above line is wrapped according to RFC 822 section 3.1.1, it would appear as follows:

When the TNEF Correlator is wrapped in the above manner, the IMAIL process in the Microsoft Exchange information store does not interpret the header correctly, and consequently it ignores the TNEF section of the message. Because message formatting, rich-text definitions, and attachments can be placed in the TNEF, they could also be lost.

To work around this problem, the originator of the message needs to turn off rich text formatting.

Microsoft has confirmed this to be a problem in Exchange Server version 5.0. A supported fix is now available, but has not been fully regression-tested and should be applied only to systems experiencing this specific problem. Unless you are severely impacted by this specific problem, Microsoft recommends that you wait for the next Service Pack that contains this fix. Contact Microsoft Technical Support for more information.

This fix has been posted to the following Internet location:
Microsoft has confirmed this to be a problem in Microsoft Exchange Server version 5.5. This problem has been corrected in the latest U.S. Service Pack for Microsoft Exchange Server version 5.5. For information on obtaining the Service Pack, query on the following word in the Microsoft Knowledge Base (without the spaces):