Article ID: 970777 - View products that this article applies to.
You send an e-mail message in Microsoft Office Outlook 2007 by using Cached Exchange mode. If one or more recipients of the message have a corrupted e-mail address or a corrupted e-mail address type, the message is retained in the Outbox folder and additional log files are generated on the Exchange server unexpectedly. However, the Exchange server does not generate a Non Delivery Report (NDR) for this problem.
To resolve this problem, install the Outlook 2007 hotfix package that is dated June 30, 2009. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
970944Note This hotfix package enables the Exchange server to generate a NDR. Additionally, the e-mail message is not sent if the recipients of the message have corrupted e-mail addresses or corrupted e-mail address types. This hotfix package also prevents log growth on the Exchange server. However, a limitation of this package is that the NDR does not contain any information about the recipients.
(http://support.microsoft.com/kb/970944/ )Description of the Outlook 2007 hotfix package (Outlook.msp): June 30, 2009
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.