XFOR: Exchange 2000 Sends MIME Plain Text as HTML and Plain Text

When a user sends a plain text message from a Microsoft Outlook client that uses an Exchange 2000 server to send messages to the Internet, the Exchange 2000 server may override the user's choice and send both plain text and Hypertext Markup Language (HTML). When MCI Mail or other plain text mail readers receive a MIME/multipart/alternative message, the recipient receives one e-mail message that contains plain text at the top followed by the same message embedded in HTML tags.

This problem can occur if the Exchange 2000 server does not receive the sender's option in the message. As a result, the Exchange 2000 server sends both the plain text message and the HTML message.

To resolve this problem, obtain the latest service pack for Microsoft Exchange 2000 Server. For additional information, click the following article number to view the article in the Microsoft Knowledge Base: The version of this fix should have the following file attributes or later:

Component: Transport

File name	Version
Phatcat.dll	6.0.4418.54

Microsoft has confirmed that this is a problem in Microsoft Exchange 2000 Server. This problem was first corrected in Microsoft Exchange 2000 Server Service Pack 1.

After you apply this fix, you must make registry changes to enable this functionality.

WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.

To enable this functionality:

1.	Stop the Exchange 2000 Server services.
2.	Apply the fix that is described in the "Resolution" section of this article.
3.	Start Registry Editor (Regedt32.exe).
4.	Locate and click the following key in the registry: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MSExchangeTransport\Parameters
5.	On the Edit menu, click Add Value, and then add the following registry value: Value name: SendPlainTextAsIs Data type: REG_DWORD Radix: Hexadecimal Value data: 0x1
6.	Quit Registry Editor.
7.	Restart the Exchange 2000 Server services.

After you add this value, all plain text mail that is generated by Outlook is sent as plain text without any HTML tags.