Restore Office365 onpremise synchronisation

change immutableids to match objectguids

Windows associates on premise Accounts with Azure AD by comparing the ObjectGUID from the local Account to the immutableID of Azure.

The following scripts use the email address as unique identifier to rejoin local and remote accounts:

Get the ObjectGUIDs ( example on linux, can be windows too):

ldapsearch -h <host> -p 3268 -D "cn=<admin>" -b "ou=<where the users are>" -W -x -s sub sAMAccountName objectGUID > /tmp/immutables

Format and create Email-Adresses:

cat /tmp/immutables | awk '/^objectGUID/{a=$2;}/^sAMA/{print$2"@<company.com>",a}' > /tmp/match

Now we switch to a Windows computer.

Copy the /tmp/match file to that computer

Start Powershell

Install-Module -Name AzureAD

Connect-AzureAD

set-executionpolicy remotesigned

Create Backup of old immutableIDs (max 2000)

Get-AzureADUser -top 2000 | Select-Object userprincipalname,immutableid > C:\users\public\BackupImmutable.txt

Set new immutables:

cat <wherever match is> | ForEach-Object{$mail,$immut=$_.split("");Set-AzureADUser -ObjectId "$mail" -immutableid "$immut"}