Hi, I have a problem with a migration from Exchange 2003 to Exchange 2007. There are 2 different forests, one with Windows 2003 with Exchange 2003 and a new one with Windows 2008 and Exchange 2007 sp1. In the new AD, all the users will be created from scratch, so there is no user migration from the old domain. However, we need to move the mailboxes from Exchange 2003 to Exchange 2007 and the move-mailbox command has a problem if it doesn't find the same user SID in both domains. Also, because there are a lot of mailboxes to be migrated, the option to use .pst EXMERGE utility is not a viable possibility. Is there any other way to move the mailboxes? Thanks in advance

Yes, the recommended approach is to use ADMT to migrate the users first and then use move-mailbox. ADMT will create the accounts in the new domain, and will preserve the SIDs. see here: http://technet.microsoft.com/en-us/library/aa997145(EXCHG.80).aspx you could also use the -ntaccountou switch instead of the -allowmerge switch, and this will create new user accounts...

Supplement: Heres another article which talk about Mailbox Movement on MSExchange Blog Exchange 2007 Cross Org Mailbox Migration

Thank you very much for your response. The problem is that there is no ADMT tool for Windows 2008 and in our case the new user accounts will already be created in the new domain. So, if I use the -ntaccountou switch it will create new users in the new domain and this is not what we want.The question is, can we use the move-mailbox command and attach the mailbox to an already existing user in the new forest, without the use of ADMT? If it'a not possible to be done with the move-mailbox command, is there any other way to accomplish the task?Thanks in advance

Heres the link to download ADMT 3.1 for Windows Server 2008 http://forums.technet.microsoft.com/en-US/winserverMigration/thread/2b44549d-ec8d-4b9d-b3d0-fb7e05c407bd/ Use ADMT to move user object to target server is a required step, per my knowledge, migrated user objected will hold original SID history which is very important, as we need it to let the account access the resources that original account has rights on. Suggest you follow the steps to deploy to avoid other potential issues

Thnak you very much. Do you know if the ADMT toll can copy the SID History to a new user?Thanks

I just found out that the new ADMT 3.1 is available for Windows 2008. I'm going to try to use the tool and I hope that it allows me to use alreasy existing users in the target AD

OK

ADMT does copy SID history.

Yes, you can easily merge our source accounts with existing target accounts. I've performed this countless times with ADMT and third-party tools, and if you are simply looking to migrate sIDHistory and no other attributes it's pretty straight forward. Use an import file that specifies the sAMAccountName, TargetRDN, and TargetUPN, then disable attribute migration on all user accounts attributes. If you don't specify the existing TargetRDN or TargetUPN in the import file, even with all attributes deselected, ADMT will still update the target accounts CN and UPN to match the source accounts. Since you already have your accounts deployed in the target forest, I doubt you want those attributes changing, especially since changes to the RDN screw-up any scripts you might have created that are referncing the previous DNs. Make sure that you disable sID filtering on all forest trusts between the source and target.

Thank you very much for your reply. I'll try to implement it and I hope it works