Set UPN Suffix using PowerShell

To Prepare for Office 365 Migration you need to add the missing ‘UPN Suffixes’.

The following example demonstrates how to create a new UPN suffix for the users in the ThatLazyAdmin forest:

Lets Start by running:

Import-Module ActiveDirectory

Then run :

Get-AdForest | Set-ADForest -UPNSuffixes @{Add="ThatLazyAdmin.com"}

Lets verify the new UPN in Active Directory Users and Computers

There you go.

#ThatLazyAdmin

For a full explanation of the parameters that you can pass to Set-ADForest, at the Active Directory module command prompt, type Get-Help Set-ADForest –detailed, and then press ENTER.