You cannot send a message to a Dynamic Distribution Group in a mixed Exchange Server 2007 and Exchange Server 2010 environment

In a mixed Microsoft Exchange Server 2007 and Microsoft Exchange Server 2010�environment, a message that is sent to a Dynamic Distribution Group fails. Additionally, you receive the following non-delivery report (NDR) message:
Note�The NDR�includes "DiscoverySearchMailbox" and "FederatedEmail" system mailboxes.�This is�unexpected. If you view the members that appears in the Dynamic Distribution Group by using Exchange Management Console, the system mailboxes are not listed. However, if you view the members that appears in the Dynamic Distribution Group by using Exchange Management Shell, the system mailbox are listed.�If the Dynamic Distribution Group is expanded on an Exchange Server 2007 server, the NDR is generated for all the Exchange Server 2010 recipients. If the Dynamic Distribution Group is expanded on an Exchange Server 2010 server, the NDR is only generated for the�DiscoverySearchMailbox system mailbox.

This problem occurs because Exchange Server 2010 does not exclude system mailboxes from a Dynamic Distribution Group.

To resolve this problem, install the following update rollup:

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

For more information about how to view members of a Dynamic Distribution Group, visit the following Microsoft website: