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Exchange mailbox migration to another forest

Created: 20 May 2013 | 3 comments


In the very near future we will be migrating our Exchange 2007 mailboxes to a different forest, hosting Exchange 2010. Our source mailboxes currently have EV archives so need to know the best way re-link the mailboxes back to their current archives once the mailbox have been moved.

I have configure EV to see the mailbox stores in the new target forest and can archive items from new mailboxes in that forest. Did this just so I could test that EV is working across the forests.

As we will be migrating across forests the mailboxes will have be created with different msExchmailboxguid and legacyExchangeDN in the new forest and need to know how to re-link these back to the orginial user archive.

EV Server will be staying in the source forest for the time being.

EV Version 9.0.2.

2 by Exchange Server 2007 in source (Forest A).

1 x Exchange Server 2010 in target (Forest B).

Thanks in advance,



Operating Systems:

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philt's picture

Not sure if these documents cover our migration but thanks anyway.

Our issue is that in the new target forest will have new user accounts and mailboxes and so they have no relationship with the old source forest user accounts and mailboxes.

Would it be possible to update the ExchangeMailboxEntry table with the new LegacyMbxDN and ExchMbxGUID from the newly created accounts and mailboxes in the new target forest.



philt's picture


I'm getting more information from the team doing the migration;

  • We are using the Quest Migration Manager to do the migration.
  • New AD accounts and new Mailboxes have been created in the new target forest (forest B).
  • Mailboxes are linked via the Quest Migration Manager system.
  • Quest Migration Manager willl copy all mail items from Source mailboxes in forest A, including the hidden message to new target mailboxes in forest B.

Still not sure how I will go about this so we don't end up with duplicate archives for each mailbox migrated. Is EVPM the tool I should be looking at and if so how would I use it?

I'm hoping and thinking some one out there has done similar migrations.

Thanks in advance.