Message headers, attachments, and the message body may be lost in Outlook 2003 when you reply to an e-mail message that contains a References header that exceeds 1,000 bytes

When you send a reply to an e-mail message in Microsoft Office Outlook 2003, message headers, attachments, and the message body may be lost. This problem may occur when the following conditions are true:

• You have security update MS07-003 for Outlook 2003 that is dated January 9, 2007 installed.
• You reply to a long e-mail message thread.
• The References header exceeds 1,000 bytes and contains a carriage return line feed (CRLF) character as the last character in the References header.
• Microsoft Exchange Server adds a new line to the References header that contains a TAB character as the first character on the new line. The new line now contains the TAB+CRLF characters.

When these conditions are true, Exchange Server interprets the TAB+CRLF characters as the end of the e-mail message when Microsoft Exchange sends the e-mail message.

To resolve this problem and to change the behavior of the References header to the behavior of the References header in earlier versions of Outlook, install the Outlook 2003 post-Service Pack 3 hotfix package that is dated December 7, 2007. Then, add the ReferencesMaxLengthInBytes setting to the registry.

How to obtain the hotfix

This issue is fixed in the Outlook 2003 post-Service Pack 3 Hotfix Package that is dated December 7, 2007. For more information, click the following article number to view the article in the Microsoft Knowledge Base:

How to enable the hotfix

Warning Serious problems might occur if you modify the registry incorrectly by using Registry Editor or by using another method. These problems might require that you reinstall the operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To enable this hotfix, follow these steps:

1. Exit Outlook 2003.
2. Click Start, click Run, type regedit, and then click OK.
3. Locate and then click to select the following registry subkey:
   HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Outlook\Options\Mail
4. After you select the subkey that is specified in step 3, point to New on the Edit menu, and then click DWORD Value.
5. Type ReferencesMaxLengthInBytes, and then press ENTER.
6. Right-click ReferencesMaxLengthInBytes, and then click Modify.
7. In the Value data box, type a number to set the length in bytes of the References header, and then click OK.
   
   Note You can set the length of the References header from 0 bytes to 998 bytes.
8. On the File menu, click Exit to close Registry Editor.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

The security update MS07-003 for Outlook 2003 that is dated January 9, 2007 enables the References header in an e-mail message to save additional information. In versions of Outlook before Outlook 2003, the additional information in the References header is erased.

For more information about the security update, click the following article number to view the article in the Microsoft Knowledge Base: