Convert ImmutableID to Hex for AD
To get the immutableID value from a user (should be able to do similar with Get-MSOLUser if preferred): $id = (Get-AzureADUser -ObjectId User@domain.com).immutableid To convert that ID to hex for entry $hex=([system.convert]::FromBase64String("$id") | ForEach-Object ToString X2) -join ' ' To view the value in $hex: $hex The immutable id will be a value something like: fhG+Kox7LkaYwSIf6s6UFA== The hex for that one is: 7E 11 BE 2A 8C 7B 2E 46 98 C1 22 1F EA CE 94 14 The hex value can be entered into the ms-DS-ConsistencyGUID attribute of the user object. And converting from objectGUID to ImmutableID $immutableID = [system.convert]::ToBase64String(([GUID]($u.ObjectGUID)).tobytearray())