Hi 

We are looking to complete 2 cross forest migrations - One from 2007 and the other from 2010 to 2013

Native tools are being used with ADMT and New-MoveRequest.  But in terms of co-existence (GAL & Free/Busy), PF's and web URLs including Autodiscover - has anyone had to complete a cross forest migration and if so are there any tips to make it as seamless as possible?  Plus any gotcha's to take care of?

Thanks 

Hi,

Following are the steps and details for a suggested cross forest migration:
1. Preparemove-> Creates MEU (Mail enabled users) at target forest in disabled state. The contacts will be containing some limited number of attributes like mailbox guid, proxy address, upn etc.
2. ADMT -> To get the SID history, password sync etc.
3. Move mailbox from source to target forest.
4. ADMT to move computer accounts.

More details please refer to below blog: Exchange 2010 Cross-Forest Migration Step by Step Guide. Also, pay attention to Exchange Queue & A: Across the Forest.

Thanks

Above suggested steps looks good to get this job done.

However, to gather more information in depth, you may also walk through below given links:

Guide for exchange 2007 to 2013 migration: http://blogs.technet.com/b/meamcs/archive/2013/07/25/part-1-step-by-step-exchange-2007-to-2013-migration.aspx

Exchange 2010/2007 to 2013 Migration and Co-existence Guide: http://msexchangeguru.com/2013/05/10/exchange2013-migration/

To accomplish this task more smoothly here an automated solution i.e. ( http://www.exchangemigrationtool.com/ ) lets you to get real-time coexistence between two Exchange Servers during the migration period