How to merge on-prem Users to Cloud-only User

Sometimes, you need to merge an on-premises user with a cloud-only user. This situation often arises in small or medium-sized companies. They may have initially adopted cloud services, such as mailboxes and SharePoint, while continuing to use on-premises Active Directory (AD) for local staff. However, without setting up a hybrid environment, they end up with two separate user accounts.

In this post, I will show you how to merge an on-premises user with a cloud-only user.

On-prem User

$onpremUser = "testuser"

$guid =(Get-ADUser $ADUser).Objectguid

$immutableID=[system.convert]::ToBase64String($guid.tobytearray())

$immutableID

So we have the immutableID of the on-prem user. Next to set it to the cloud user.

Cloud User

Connect-AzureAD

$cloudUser = "otheruser@domain.com"

$aaduser = Get-AzureADUser | ?{$_.UserPrincipalName -like $cloudUser}

Merge the users

Set-AzureADUser -ObjectId $aaduser.ObjectId -ImmutableId $immutableID