The most common failures are caused by an object in the Active Directory store being deleted or created (perhaps after unintentional deletion was discovered) without using the Microsoft Provisioning System (MPS).
Objects created outside of MPS may appear to be present in the Active Directory store, but they cannot be provisioned.
In the case of deleted objects, MPS maintains references to a deleted object and further provisioning, monitoring, and reporting attempts relating to that object will fail.
Deleted objects may also leave orphaned data and resources that MPS has not freed. These resources can only be freed by reinstating the original object from backup and then deleting it using MPS. Only in this way can MPS clean up data and resources. See An Object Is Deleted in the Active Directory Store for more information.