When you perform a hard matching via PowerShell and you notice that once you run the Set-MsolUser command on the correct account, it return an error “Uniqueness violation. Source anchor”. Hmm what could be the cause for this error???
Well the reason for the cause of this error is obvious that there is still existing duplicated account is still not fully removed from Active Users list and Recycle Bin.
This post requires you to know the basic commands like Connect-MsolService, Set-MsolUser, Remove-MsolUser and Get-MsolUser.
So what you got to do is to run the remove command to remove the duplicated account. Once fully remove from the Active Users list and Recycle Bin, you could continue to set the immutable ID on the correct account.
Oh yea….if the account that you wish to set the new or correct immutable ID make sure it is empty or cleared before you set the new or correct ones.