XIMS: Internet Mail Service Does Not Generate Non-Delivery Report Message If Number of Recipients Exceeds 32,766

A message in the Imcdata\In folder may never be delivered and may remain in that folder. If you stop and restart the Exchange Server Internet Mail Service, the message may be redelivered to most of the recipients of the message.

The following event ID 4120 error message is logged in the application event log: The following event ID 4131 error message may be logged in the application event log as well:

This problem can occur if the message has more than 32,766 (0x7FFE in hexadecimal numbers) recipients defined. The Internet Mail Service uses Messaging Application Programming Interface (MAPI) to create non-delivery report (NDR) messages, and attempts to add the recipients to an NDR message that MAPI is creating. MAPI uses the Emsmdb32.dll file to communicate with the information store, and the Emsmdb32.dll file has a limit of 32,766 recipients defined for the number of recipients on a single message.

A supported fix is now available from Microsoft, but it is only intended to correct the problem that is described in this article. Apply it only to computers that are experiencing this specific problem. This fix may receive additional testing. Therefore, if you are not severely affected by this problem, Microsoft recommends that you wait for the next Microsoft Exchange Server version 5.5 service pack that contains this hotfix.

To resolve this problem immediately, contact Microsoft Product Support Services to obtain the fix. For a complete list of Microsoft Product Support Services phone numbers and information about support costs, visit the following Microsoft Web site:NOTE: In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The typical support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

The English version of this fix should have the following file attributes or later:

Component: Internet Mail Service

Microsoft has confirmed that this is a problem in Microsoft Exchange Server version 5.5.

This fix has two parts and addresses both the message that is already in the Imcdata\In folder and new messages that arrive to the Internet Mail Service with more than 32,766 recipients.

For the message in the Imcdata\In folder, the basic problem is the inability to create an NDR because of the number of recipients. This fix creates the NDR with 32,766 recipients and does not show the rest in the NDR. The following new event ID has been created to report this exceptional circumstance: If a new message is delivered to the Internet Mail Service, the server sends a 452 response when the number of recipients being submitted exceeds 0x7FFE. This response is an indicator to the sender that another message needs to be submitted with the remaining recipients (in other words, that the sender needs to break the message into multiple messages with fewer recipients on each message). For additional information about the hotfix in this article, click the article number below to view the article in the Microsoft Knowledge Base: