Hi,

I am working on the planning to achieve the cross forest migration for exchange 2010 with an upgrade to 2013.

in my environment Exchange 2010 is deployed in Resource forest and all the mailboxes are linked with their users in user forest.

now problem is how to get this migration done and how these linked mailboxes will be connected to their users in user forest after migration.

need food for thoug

HI Owais,

Can you clarify something for me. You have two forests currently.

One is the user forest, the second is the Exchange 2010 forest.

Where are you planning on deploying Exchange 2013? Is Exchange 2013 being deployed into the User Forest?

Let me know,

Oliver

Hi Oliver,

yes I have user forest and exchange forest... now we are planning to deploy exchange 2013 in user forest... where all users have their linked mailboxes in the exchange forest...

Hi,

According to your description, I understand that you want to migrate Exchange 2010 to Exchange 2013 within account forest and resource forest.
If I misunderstand your concern, please do not hesitate to let me know.

I recommend we use a shared name space on two Exchange server.
If theres several account within your environment, we can use export and import PST file to achieve your goal.
Basically give the user a new mailbox to their account and get them working in Account forest, then dealing with new mail and in the background have the old mail data getting imported.

Additional, heres the blog about Exchange 2010 Cross-Forest Mailbox Moves:
http://blogs.technet.com/b/exchange/archive/2010/08/10/3410619.aspx

Thanks

-          We have 2 forests, one is resource forest hosting Exchange 2010 and one is user forest hosting all users.

-         All mailboxes in the resource(exchange) forest are linked to the users in user forest.

-         Now I want to deploy Exchange 2013 in the user forest and migrate the mailboxes.

What would be the best approach to deploy exchange and migrate the linked mailboxes to the users with their existing mails.

Hi,

Would you want retain the account in Account forest?

If you want leave original account, we can convert linked mailbox to user mailbox, then deploy cross-forest migration with new user account.
More details about Convert linked mailbox, please refer to: https://technet.microsoft.com/en-us/library/bb201694(v=exchg.141).aspx

Thanks

Hi Allen,

if i will convert linked mailboxes to user mailbox in the resource(exchange) forest than the master account will be lost, and users will not be able to connect to their mailboxes.

Hi,
Good resources are suggested above might be you have sorted out your problem.

If not, then I would like to share a good informative resource that provides complete guide to accomplish cross forest migration: http://msexchangeguru.com/2013/11/03/e2013crossforestmigration/ 

Moreover, if you wish you may also give a try to this solution ( http://www.exchangemailboxmigration.com/ ) that would be a nice option to done this job.