I keep getting message delivery failures in my Exchange 2007 Message Tracking log

Symptoms

On my Exchange 2007 server I keep getting message delivery failures in my Message Tracking log. It appears that some email messages have no Sender email address and no MessageSubject.’

Please note – this functionality is by design. If you have an Exclaimer Mail Utilities rule that modifies the Sender field, Exchange 2007 will identify that the Sender field has been modified and will record a failure on the message as the Sender field is changed. The message will still be delivered as per your Exclaimer Mail Utilities rule.

Resolution

To stop delivery failures appearing in the Message Tracking log you should not use rules that modify or delete the recipient(s) from an email. These types of rule typically use features found in the Delivery Options tab of the Custom Rules box.

More Information

If you were to set up a rule that replaces an email recipient, Exclaimer Mail Utilities would remove the original recipient (e.g. ben@exclaimer.com) and add a new one (e.g. bill@anotherdomain.com). Exchange 2007 will log a delivery failure in the message tracking log against ben@exclaimer.com because delivery to him has 'failed'. The message has instead been sent to the new recipient bill@anotherdomain.com exactly as you specified in the rule.