When you send an e-mail message to recipients in a distribution list for which only the Mail property is set, the e-mail message does not leave the SMTP queue in Exchange Server 2003 (923891)

Important This article contains information about how to modify the registry. Make sure to back up the registry before you modify it. Make sure that you know how to restore the registry if a problem occurs. For more information about how to back up, restore, and modify the registry, click the following article number to view the article in the Microsoft Knowledge Base:

256986 Description of the Microsoft Windows registry

SYMPTOMS

Consider the following scenario. In Microsoft Exchange Server 2003, you send an e-mail message to recipients in a certain distribution list. Only the Mail property is set for this distribution list. In this scenario, the e-mail message does not leave the SMTP queue.

CAUSE

This behavior occurs if one of the following conditions is true:

Exchange Server 2003 is operating in Native mode.
You upgraded Microsoft Exchange 2000 Server to Exchange Server 2003.

By default, Exchange Server 2003 sends messages in the Summary TNEF (S/TNEF) format instead of in the Transport Neutral Encapsulation Format (TNEF) format.

WORKAROUND

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 your operating system. Microsoft cannot guarantee that these problems can be solved. Modify the registry at your own risk.

To work around this behavior, follow these steps:

Click Start, click Run, type regedit, and then click OK.
Locate and then click the following registry subkey:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Exchange
Right-click Exchange, point to New, and then click Key.
Type StoreDriver, and then press ENTER.
Right-click StoreDriver, point to New, and then click Key.
Type Exchange, and then press ENTER.
Right-click Exchange, point to New, and then click Key.
Type 1, and then press ENTER.
Right-click 1, point to New, and then click DWORD Value.
Type EnableTnef, and then press ENTER.
Right-click EnableTnef, and then click Modify.
In the Value data box, type 1, and then click OK.

Note When you set the EnableTnef registry entry to 1, Exchange Server 2003 sends messages in the TNEF format only.
Exit Registry Editor.

MORE INFORMATION

You can use the following values with the EnableTnef registry entry:

0: When you set the EnableTnef registry entry to 0, Exchange Server 2003 does not generate messages in the TNEF format or in the S/TNEF format.
1: When you set the EnableTnef registry entry to 1, Exchange Server 2003 generates messages in the TNEF format only. The Exchange server will never send a message in the S/TNEF format.
2: When set the EnableTnef registry entry to 2, Exchange Server 2003 generates messages in the S/TNEF format only. The Exchange server will never send a message in the TNEF format.