ADC May Create New, Empty Mailbox in Exchange Server 5.5

The Active Directory Connector (ADC) may create a new, empty mailbox in Microsoft Exchange Server 5.5. This issue occurs when you are using the ADC in an Exchange Server 5.5 and Microsoft Windows 2000 Active Directory environment, and involves the following conditions:

If you add only the mail attribute on a user in Active Directory, the ADC does not match an Exchange Server 5.5 mailbox to that user, nor does it create a disabled user.

Instead, a custom recipient is created in the Exchange Server 5.5 directory with the same e-mail address as the mail attribute on the Active Directory user. If this Simple Mail Transfer Protocol (SMTP) address matches that of a real mailbox in Exchange Server 5.5, it breaks the mail flow for that mailbox.

Now, if you attempt to resolve this, you may end up with two mailboxes in the Exchange Server 5.5 directory. This may occur if you delete the custom recipient, and clear all of the mail-enabled attributes off the Active Directory user. If you then re-replicate the Connection Agreement (msExchDOFullReplication = TRUE), and you find two mailboxes in Exchange Server 5.5, one is the real mailbox, and one is an empty mailbox that is created by the ADC. The Active Directory user is matched to the new, empty mailbox.

To resolve this problem, obtain the latest service pack for Microsoft Exchange 2000 Server. For additional information, click the following article number to view the article in the Microsoft Knowledge Base: The English version of this fix should have the following file attributes or later:

Component: ADC

Microsoft has confirmed that this is a problem in Microsoft Exchange 2000 Server. This problem was first corrected in Microsoft Exchange 2000 Server Service Pack 2.