Office 365 with AD connect - Migrating user cross forest using Active Directory Migration Tool

[Marvin Oco]

Scenario:

- Migrating user cross forest using Active Directory Migration Tool

- AAD connect is in place in OLD AD forest

- Will add new forest in AAD sync scope

Once users is moved to new forest, how do we Match AD user to his existing O365 mailbox profile?

Thanks

[#2]

HI @Marvin Oco 

After migration of users objects into New Forest, Keep those users into one specific OU and change the attribute by PowerShell. You need to change the Immutable ID of each office365 user.

I hope below link will also help you:

https://msexperttalk.com/understand-and-modify-office365-users-immutableid/