Exchange - How to convert a linked Mailbox to a User Mailbox in a migration scenario

whenz used Ask the Experts™
please find the scenario in the attached picture.

Question:  How do I ensure that Andy Meyer gets a new AD Account in the new domain with keeping his existing Exchange Mailbox?
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Why are you creating new accounts in You already have AD accounts for all your users. Just enable the disabled accounts and reset the passwords.

If you must have the new accounts, You can delete all the current disabled accounts in and reconnect the mailboxes to the new accounts.


Hi Jamie,

Thank you for the input.  We have to re-create those accounts because of the following reason:

Until now the AD accounts were created manually by the helpdesk team.  We are going to introduce an Identity Management system where all the user accounts gets created new using the IDM.  I know it sounds crazy as we have to re-create all from scratch (ntfs permission, application permissions etc).  But that's what the management wants.

I will have a look into the link you sent me, thank you for the input!
Saif ShaikhServer engineer

The picture resembles a cross forest migration of AD account and mailboxes. But here you are not migrating the existing AD account using ADMT tool, but you are creating altogether new AD account which has a new SID.

So in this case how can you migrate the existing mailbox which was attached to the old existing AD account.

You will have to take out PST from old mailboxes, create new mailboxes for the new AD accounts and then import PST from old mailbox.

I think this is what needs to be done.

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