Each user account or security group is uniquely identified with a SID (Security ID) and a GUID (Global Unique ID). If a user or group has been deleted, and is then re-created with the same name, the SID and GUID of the newly created user or group will differ from those of the deleted object. As a result, the new user or group loses all permissions, profile settings, and all other settings associated with the old SID and GUID.
When you restore a deleted user or group from a backup, the restored user or group will have the same SID and GUID as the deleted object, and will have all the settings associated with that SID and GUID.
You can restore individual objects using the Online Restore feature of Recovery Manager for Active Directory. Alternatively, you can restore the entire Active Directory database, and then select individual objects for authoritative restore.
While Recovery Manager for Active Directory supports both methods, online restore is the recommended option as it is faster and simpler. The online restore method allows you to easily restore individual directory objects and object attributes without restarting domain controllers and putting Active Directory offline, thus achieving near-zero downtime.