Before migrating users from one Enterprise Vault (EV) managed Exchange server to a new Exchange server, an archiving/retrieval service/task must be created for the new Exchange server and also ensure that the Vault Service Account (VSA) has all the corresponding permissions necessary on the new Exchange server as it did on the old.
It can be useful to make EV automatically assign migrated mailboxes to existing archives.  There is a DWORD registry value, SynchInMigrationMode that controls whether the automatic association takes place. Create SynchInMigrationMode under the following registry key on the Enterprise Vault Server BEFORE starting the mailbox migration to the new Exchange server:

HKEY_LOCAL_MACHINE
\Software
\KVS
\Enterprise Vault
\Agents

Give SynchInMigrationMode a value of 1 to make EV assign new mailboxes to archives that are associated with the same legacyMbxDN values.
Give SynchInMigrationMode a value of 0 to use the default behavior, in which EV does not assign new mailboxes to archives that are associated with the same legacyMbxDN values.
SynchInMigrationMode affects only the association between user mailboxes and archives; it does not affect the association between journal mailboxes and their archives.
This generally helps when migrating mailboxes from one server or mail store to another, in order to prevent duplication of entries in the ExchangeMailboxEntry table.


The basic procedure for moving mailboxes to a new Exchange server are outlined below.

Note: Please refer to the EV Installing and Configuring guide for steps on adding & configuring the Exchange server services/tasks.

1. Configure the EV permissions on the new Exchange server. This can be completed before the move.

a. Make sure you add the VSA to the Local Administrators group on the new Exchange server(s).

b. Delegate the VSA Exchange Admin rights at the organizational or admin group level.

c. Make sure the VSA is not part of any Active Directory (AD) Admin type groups. It should only be a domain user.

Reason: The domain admins group has explicit 'Send As' and 'Receive As' permissions DENIED.

2. Configure an Outlook profile on the EV server that can logon to the new exchange server.

3. Configure a new task under 'Tasks' to connect to the new server name.

a. The creations of the tasks will create a new system mailbox on the Exchange server.

b. Start the new task and wait a few minutes then refresh the screen and verify the task is still running. If having any problems then check the event log.

c. Within the task synchronize all users.

4. Move the users.

a. Sync the users on the new server using the synchronization tab.

b. Check EV functionality. Verify the user can access their vaulted items and verify that the user can vault items if this is allowed.

Once migration of mailboxes has occurred EV will need to be synchronized against the new Exchange servers.

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