Immutable identifier to maintain relationship between ADDS and Microsoft Entra ID. Used by both password hash sync, pass-through authentication and federation. Used to know when to invalidate already issued tokens. AD user identifier used to maintain sync between Microsoft Entra ID and AD. Microsoft 365 Apps for enterprise Attribute Name Unselecting other attributes might have a negative impact on features.

When deselecting attributes, you should be cautious and only deselect those attributes absolutely not possible to synchronize.