Now as days one of the major migration project handled by exchange administrators are Moving mailboxes from Exchange 2003 to Exchange 2010. When doing this, we should have a proper roll back plan, when we required to move back the mailboxes migrated to Exchange 2010 back to 2003.

Recently one of the customer has requested me to include the steps in the migration plan. I have prepared it as follows:

The reference from Microsoft KB collection for this is found here: http://technet.microsoft.com/en-us/library/dd638157.aspx

1. The first step is to disable the Personal Archive as this is an exclusive feature on Exchange 2010 only. The following cmdlet can do the job

Disable-Mailbox -Identity <identity> -Archive

2. The next step is if ‘SingleItemRecoveryEnabled’ property is ‘True’, this should be disabled by using the following cmdlet:

See if the property is enabled:

get-mailbox <identity> |ft displayname,singleitemrecoveryenabled    

Disable it using the following cmdlet:

set-mailbox <identity> -SingleItemRecoveryEnabled $False

3. Next step is to delete any Retention items presented with Exchange 2010 mailbox. You will need to clear these out before the mailbox is moved to Exchange 2003.

Your admin account should the member of  ‘Discovery Management’ USG in Exchange 2010 to search mailbox for retention items presented in the mailbox.  The following cmdlet can add your username to the particular USG

Add-RoleGroupMember -Identity “Discovery Management” -Member <your account name>

Next is to search the mailbox

Search-Mailbox -Identity <identity> -SearchDumpsterOnly -estimateresultonly |fl Identity, ResultItemsCount, ResultItemsSize

If the properties ResultItemsCount and ResultItemsSize are >0 you will need to clear these out before the mailbox is moved to Exchange 2003. Use the following cmdlet for this

Search-Mailbox -Identity <Identity> -SearchDumpsterOnly -TargetMailbox “Discovery Search Mailbox” -TargetFolder “<Identity>-RecoverableItems” -DeleteContent

Search the mailbox again to confirm the operation

4. Now we are ready to move the mailbox back to Exchange 2003. But we need to find the database GUID of the Exchange 2003 database to substitute in the cmdlet:

(get-mailbox -database “Exchange 2013 Server Name\Storage Group 1\Mailbox Database 1” | select -first 1).database

The result includes a property called ObjectGuid property and which is will help to identify the correct hive in the registry on the Exchange 2003 server to find the GUID easily

The move cmdlet can be built as below: This is handled in two ways for ‘Same Forest’ as well as in ‘Cross Forest’

For ‘Local’ Move (Same Forest):

new-moverequest -identity “Identity” -targetdatabase GUID

For Remote Move (Cross Forest):

$UserCredential = Get-Credential

New-MoveRequest -identity “Identity” -remotelegacy -RemoteTargetDatabase “DB Name” -RemoteGlobalCatalog “GC Name” -RemoteCredential “$UserCredential” -TargetDeliveryDomain “Domain Name”

Exchange 2010 will be queuing the move request and can be monitored from the Exchange Management Console to see the status.

Hope this helps you in your Migration Rollback activity