Email Migration

PC4N6 used Ask the Experts™
I have been asked to look at an email conversion. There are 2 domains A and B.  Users in do have Active Directory user accounts in b/c of their phone system.  My users in need to have all of their email moved to and then start using as their only domain.  I am planning on joining the user workstations to the domain.  What would be the best way to migrate the mailboxes from to  I can't use a trust between the 2 as there are naming conflicts. is using Exchange 2003 and is using Exchange 2007.
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If you cant do a trust you may end up needing to use exmerge to export and then import the users mail from the old domain to new.

You may also want to take a look into the quest exchange migration tools. I dont know if they can support a migration without a trust but they may be worth checking out.

• Export Exchange 2003 Mailboxes as PST files and manually move them to the domain.
You can do a cross-forest migration thru powershell with a two-way trust,

Depending on how many mailboxes there are and the work resources that you have, using exmerge will be mroe efficient and beneficial, though if your organization has alot of mailbox, do this thru powershell would be more effective, since you can target several targets at once when moving.

Since you said that the users in your A domain already exists in your B domain, this might become more troublesome, im under the impression that the user accounts needs to have the same SID, so when migrating mailboxes thru powershell, the migration process needs to know where to "attach" the mailbox in the new domain, and by default it "assumes" that the users should have the same sid.

If you would have exchange 2010 you could use microsofts "PrepareMoveRequest.ps1", doing a cross forest migration with the same user already existing in the new domain is hard and alot of work, if you have further questions feel free to ask,

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I would love to use the powershell and move the mailboxes that way, but the bigger problem (even bigger than the users already having accounts in the target domain) is that we don't and can't create a trust between the domains.  The source domain is already being used in the target domain, so we would have to rename the domain before proceeding.  There is only 80 mailboxes at this office so it is sounding like exmerge to a .pst and then import with exmerge to the target will be the viable answer.  Can anyone suggest any other means of doing this project?
Unfortunately without being able to set up a trust between the domains I think you will be stuck going the exmerge route.
You should be able to setup a two-way trust using ip addresses instead of FQDN, though this wouldnt help since users already have an account on respective account. If its only 80 mailboxes doing this with exmerge is definetly the best choice in my opinion =)


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