Trying to perform a cross-forest Exchange 2010 SP2 --> Exchange 2010 SP2 Migration (w/ ILM, and Prepare-MoveRequest.ps1 )

Hello,

I am trying to migrate mailboxes between seperate AD Forests /Exchange Orgs. We have trusts in place, and a parent organization is running GalSyn (ILM) replicating the respective user objects as Mail Enabled Contacts. We also unfortunately had user accounts pre created via batch (ADMT, Prepare-MoveRequest.ps1 / vbs was not used) I am able to run Prepare-MoveRequest.ps1 from the target;

H:\dev\PowerShell\O365Migrations\Scripts\Prepare-MoveRequest.ps1 -Identity kjammi@SourceCompany.com -RemoteForestDomainControl

ler irv-corp-dc1.corp.SourceCompany.com -RemoteForestCredential $creds -LocalForestDomainController atl6wdc08.na.TargetCompany.int -TargetMailUserOU (GET
-QADUSER KJAMMI -SERVICE NA.TargetCompany.INT).ParentContainerDN  -LocalForestCredential  $ATCCreds -UseLocalObject -Verbose

And one of the things of note is that the Prepare-MoveRequest.ps1 is creating a new user account-

Name                               Type                               DN                                                                                     whenCreated

----                                         ----                               --                                                                                        -----------

kjammi                                  user                               CN=kjammi,OU=Employees,OU=NonSC... 3/1/2013 11:17:55 AM

Jammi, Kiran                        user                               CN=Jammi\, Kiran,OU=Employees,O...        7/30/2013 9:15:19 PM

Jammi, Kiran                      contact                            CN=Jammi\, Kiran,OU=GAL_SYNC,DC...     7/30/2013 9:30:50 PM

I am trying to see if there is a way that if I were to try again on another account, and change the directory name, and UPN on the target account to match the source ahead of time,to force this script to detect the remote user, since there is this caveat in a section the most relevant blog I’ve found –

http://blogs.technet.com/b/exchange/archive/2010/08/10/3410619.aspx

the PrepareMoveRequest script supports 2 scenarios:

1. Creating a brand new user in the local forest where the MBX will be moved to.
2. A local recipient, either a MEU or MEC already exists, created by an external agent such as ILM - If the local forest object is a mail contact, the script will convert the mail contact to a mail user while persisting the contact's existing exchange-related attributes. If the local forest object is a MEU, the script will reuse this mail user and stamp the essential attributes on the local mail user object. The administrator must specify the -UserLocalObject switch in order to tell the script to use this scenario.

Note: The scenario that the script doesn't support is that some external process created a local user object and relies on the script to copy all the attributes and links from the remote MBX to the local user. This is the ADMT scenario described after this scenario.

In order to run New-MoveRequest cmdlet to move a mailbox from an Exchange 2003/2007/2010 source forest to an Exchange2010 target forest, the target forest must contain a valid MEU account with the set of AD attributes described in this section. These attributes are synchronized by the PrepareMoveRequest script.

There are certain mandatory attributes that should be present on the target mail user for New-MoveRequest to run properly. These attributes are always set by the PrepareMoveRequest script, either as they are taken from the source MBX, or as determined by the script. The attributes are listed here http://technet.microsoft.com/en-us/library/ee861103.aspx.

Can anyone confirm if there is a way to target an existing user for migration? Also, when trying to migrate the mailbox, with a  new-moverequest run on a target Exchange server;

I get 'Target user * already has a primary mailbox. Even though no mailbox exists for that user. Any suggestions would be appreciated!

Thanks,

Jon