XCON: How to Generate Application Log Events for Non-Delivery Report Failures

A provision to identify the root cause of a non-delivery report (NDR) is available after you set diagnostic logging on the Transport Categorizer to Field Engineering (Level 7). The resulting Event identifies the function, reason for failure, recipient name, and recipient type. After you enable Field Engineering diagnostic logging on the Categorizer, the following event is generated for messages that produce NDRs:

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.


You must manually change the Categorizer registry entry to enable Field Engineering (Level 7) diagnostic logging. To do so:

1. Start Registry Editor (Regedt32.exe).
2. Locate the Categorizer value under the following key in the registry:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\MSExchangeTransport\Diagnostics
3. Double-click the Categorizer entry in the right pane, and then change the value to 7.
4. Quit Registry Editor.

This works most of the time, but there may be scenarios when the resulting Event ID 9000 is missing some or all of the troubleshooting information, including the identity of the function, reason for failure, recipient name, or recipient type, and therefore, will not be useful.