Saturday, August 6, 2016

Cross Forest Migration Exchange 2003 to Exchange 2010

We are migrating customer Exchange environment to Office 365 but in customer environment still some forest are in legacy Exchange 2003, as you know first we have to do stage migration to Exchange 2010 than Office 365. Here i will explain here how we can go steps by steps to migrate legacy environment without third party tools.

LAB details

Target Forest -
Source Forest -

Create trust between the forest

First of all we have to create the trust in between the forest, you can create two way transitive trust and you can set the permission as per business requirement, for creating the trust you can follow here "Create Active Directory Trust"

Install ADMT on Target DC

Second steps is to install the ADMT tool in target domain controller, click here for step by steps ADMT installation

Also you can planning to migrate Users with Password , You can Configure “Password Export Server” in the source domain.


First, create OU in Active Directory such as Target Users & LAB Users

Now open Exchange 2003 console

Select the user's in source forest and check the users details

Now its time to migrate one pilot user, first  will migrate the mailboxes from source forest to target forest with using of prepare move request to prepare the move mailboxes. Before move request you have to give the credential .

now you can see the disable account in target domain.

Now its time to migrate the user's SID to enable target user, just verify the services is running

now open ADMT console

Select user account migration

provide the source and target forest information

Now select the users

Next select the user
Select the target OU where we need to migrate user

Select Password option and select "Migrate password"

its time to select the account transition and select "Migrate user SIDs to target domain"
Next Admin Account for authentication

now select option users group memberships
Click next
Next select the Migrate and merge conflict objects from conflict management wizards

Now you can see the user migrated successfully.

Now time to check the users SID history

Once you check the SID history time to run the New-Moverequest for migrating the user from source to target, as we already run the prepare move request.

Now you can verify from Exchange 2010 console user is migrated successfully.
You can also remove the move request

Now user won’t be able logon on the new forest directly as you required to change password as first logon

To avoid this situation we need to modify the users attribute

Open Active Directory Users and computers – View – Advance Features

Go to User properties – Attribute Editor

Set “PwdLastSet” attribute to –1

Open Adsiedit –Set pwdlastset to –1

user will not get password change option in next logon.

Its time to test users profile in via configuring the outlook.

Bulk Migration

First of all export all users account in CSV file with help of CSVDS -d command

Once export all users in csv prepare move request

Now you can see the status

Check the status in target domain

Now you have to follow same process as above

Once complete run the New-Move request for complete the migration for all mailboxes

Now you can on Exchange 2010 console

Also verify in target OU
Remove the move request

Now its time to decommission Exchange 2003 server, before that check the any users mailboxes are there or not.

Click here for decommission Exchange 2003 step by steps

Once all Exchange 2003 mailboxes migrated to Exchange 2010, now its time to migrate mailboxes to Exchange online.

Thank You!

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