Hi,
in one organization two domains A and B. A - Exchange 2010 and B - Exchange 2013. Migration from A to B by Cross-Forest
https://blogs.technet.microsoft.com/meamcs/2011/06/10/exchange-2010-cross-forest-migration-step-by-step-guide-part-i/
On users PC used outlook 2010. After migration, i remove outlook profile (control panel - mail - manage profile), and create new. Setting set up automatically, and everything is going well.
When the user run outlook, it comes blank and hangs, and not responds, only kill process help. like no coonection to server.
Then I go control panel - software - outlook - Restore, reboot - and then outlook start and user can connect to server well. But in the organization of more than 1,000 members, and all migrated user have this problem.
I try, run safe mode 1 or 3, remove profile by regedit, no luck :(