Mailboxes getting migrated to a mailbox store other than the store specified in Migration options. (NETIQKB56310)

  • 7756310
  • 02-Feb-2007
  • 13-Mar-2008


Exchange Migrator 2.x

Mailboxes getting migrated to a mailbox store other than the store specified in Migration options.

Mailboxes are getting migrated into an "orphaned" state on the target mailbox store

Mailboxes are not getting merged on the correct Active Directory account, instead, the Active Directory account is getting mailbox enabled to a mailbox in the first Mailbox Store on the first Storage Group while an additional mailbox is getting created in the correct Mailbox Store (as per the Exchange Migrator project options) and that mailbox is not linked to any Active Directory account.

When you upgrade the forest to a Microsoft Windows Server 2003 native forest functional level, the Recipient Update Service may overwrite the value of the homeMDB attribute for new Microsoft Exchange Server 2003 users. This behavior may cause the mailboxes for the new Exchange Server 2003 users to be rehomed on the first Mailbox Store in the first Storage Group.


In Windows Server 2003, the homeMDB attribute is marked for Linked Value Replication (LVR). When you set the forest to a native forest functional level, the forest changes the way objects replicate with regard to LVR. When an object that has LVR attributes replicates to other domain controllers, the object replicates the non-linked attributes first. Then, the object replicates the LVR attributes that follow in a separate replication packet.

This behavior causes the Recipient Update Service to see an Active Directory account WITHOUT the homeMDB attribute present. This behavior occurs even when this attribute exists on the original domain controller. Therefore, the Recipient Update Service overwrites the value of the homeMDB attribute if either of the following attributes exist:

  • The msExchHomeServerName attribute
  • The homeMTA attribute


To resolve this problem, you must modify the purportedSearch attribute before you upgrade to a Windows Server 2003 native forest functional level. To do this, follow these steps:

  • Start Active Directory Service Interfaces (ADSI) Edit. 
  • Double-click the Configuration container, expand CN=Services, expand CN=Microsoft Exchange, and then expand CN=<ExchangeOrganizationName>. 
  • Click CN=System Policies. 
  • In the right pane, right-click CN=Mailbox Enable User, and then click Properties. 
  • Scroll down to select the purportedSearch attribute, and then click Edit. 
  • Clear the attribute, and then use the following filter to configure the attribute: (&(objectCategory=person)(objectClass=user)(mailnickname=*)(homeMdb=*))  
  • Click OK to save the change, and then close ADSI Edit.

Verify that 'Mailbox Enable AD Account' Mailbox Store policy is not configured to set the HomeMDB value for newly created mailboxes


Please see the following Microsoft Knowledgebase article 903291 for more information:

Recipient Update Service may overwrite the value of the homeMDB attribute for new Exchange Server 2003 users

Additional Information

Formerly known as NETIQKB56310