Some users have new empty mailboxes that point to the first mailbox store in the first storage group after you perform an authoritative restoration of Active Directory in Exchange Server 2003

Consider the following scenario in Microsoft Exchange Server 2003:

• A Windows Server 2003 forest is set to a native forest functional level.
• An organizational unit (OU) that contains two thousand to three thousand Exchange Server 2003 users is accidentally deleted.
• These users are mail-enabled. Their mailboxes are located across several mailbox stores or storage groups.
• The users' original mailboxes are in a disconnected state in their respective mailbox stores.
• As an administrator, you perform an authoritative restoration of the Active Directory directory service.

In this scenario, some users who have mailboxes in store 2, in store 3, or in store 4 now have new empty mailboxes that point to the first mailbox store in the first storage group.

This problem occurs because the Windows Server 2003 forest has been set to a native forest functional level. This condition introduces a feature that is called Linked Value Replication. This feature lets unlinked values be replicated first, followed by linked values.

After an authoritative restoration of Active Directory occurs, the mailnickname and msExchHomeServerName attributes are replicated. However, the HomeMDB and HomeMTA attributes are not seen on all domain controllers immediately.

The authoritative restoration causes the update sequence number (USN) of the user to increase by 10000. Therefore, the Recipient Update Service determines that the objects have to be reevaluated.

The Recipient Update Service identifies the Exchange Server values that have already been replicated. Additionally, the Recipient Update Service stamps the missing HomeMDB and HomeMDA attributes on the User object before the Exchange Server 2003 server can replicate the HomeMDB and HomeMDA attributes. Therefore, a mailbox is created in "mailbox store 1" of "storage group 1" on the server. As soon as an e-mail message arrives in the mailbox, the e-mail message appears in the wrong storage group and in the wrong mailbox store.

To prevent this problem, use one of the following methods before you perform the authoritative restoration.

Method 1: Disable the Recipient Update Service

Disable the Recipient Update Service on the server that is running Exchange Server, and then perform the authoritative restoration. As soon as the authoritative restoration is finished and the Active Directory information is replicated across all domain controllers, you can enable the Recipient Update Service again. Then, you see all the required attributes, and no mailboxes are re-homed.

Method 2: Change the filter for all system and recipient policies

You can change the filter for all system and recipient policies. When you do this, the user objects will include linked value attributes. This causes the Recipient Update Service to wait until all attributes are replicated to the user before the Recipient Update Service acts.

For more information, click the following article number to view the article in the Microsoft Knowledge Base: To merge the data after the problem that is discussed in this article has occurred, follow these steps:

1. Verify that all the new mailboxes have been created in the First Storage Group on the First Mailbox Store. The rest of this recovery process assumes that the new mailboxes have been created.
2. Stop the SMTP service on the server that has duplicate mailboxes to prevent any new incoming mailflow.
3. Obtain a backup of the existing Mailbox Database First Storage Group on the First Mailbox Store. To obtain the backup, use ExMerge to capture the e-mail that was delivered to the empty mailboxes.
4. Disconnect all the existing and smaller mailboxes from the affected User Accounts by using the Remove Exchange Attributes option.
5. Reconnect all the old and larger mailboxes to the affected User Accounts.
6. Start the SMTP Service to enable new mailflow to the user mailboxes.
7. Restore the mailbox data by using ExMerge to import the data from the smaller mailbox into the existing old and larger production mailbox.
8. Run the cleanup agent on the SG1 MBX1 to show all mailboxes that are disconnected.
9. Remove all duplicate mailboxes that are disconnected.

Note All the duplicate mailboxes should have been created in the First Storage Group on the First Mailbox Store on the server. Therefore, the First Mailbox Store is the only database that you have to back up in order to merge data. When you use the Recovery Storage Group option to merge data, the user mailbox must be in the same location when recovery is run and when the backup was made. Therefore, the Recovery Storage Group option is not the best option to back up the data. Users who have had their mailboxes moved to another store or who have been deleted cannot be directly recovered by using a recovery storage group.

How to recover from this issue

1. Verify that all new mailboxes have been created in the First Storage Group on the First Mailbox Store. The rest of this recovery process assumes that this has occurred.
2. To prevent new mail from coming in, stop the SMTP service on the server that has duplicate mailboxes.
3. Use ExMerge to back up the existing mailbox database (First Storage Group) on the First Mailbox Store. All duplicate mailboxes should have been created in the First Storage Group on the First Mailbox Store. Therefore, this should be the only database that you have to back up for merging data. Using a Recovery Storage Group for merging data requires that the user mailbox be in the same location when recovery is run and when the backup is created. Therefore, it is not the best option for backing up the data. Users who have had their mailboxes moved to another store or who have been deleted cannot be directly recovered by using a Recovery Storage Group.
4. Disconnect all the existing smaller mailboxes from the affected user accounts.
5. Reconnect all the old, larger mailboxes to the affected user accounts.
6. Start the SMTP service to let new mail come to the user mailboxes.
7. To import the data from smaller mailbox into the existing old, larger production mailbox, restore the mailbox data by using ExMerge.

For more information, click the following article number to view the article in the Microsoft Knowledge Base:

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