I am trying to add users and update their privileges to a feature dataset using ArcCatalog, which has no users currently (and I am not sure why). I have tried to add privileges to both the versioned and unversioned versions of this dataset. I can enter the user (DOMAIN\USER) and select the privileges. When I click on Apply, the system chugs away, then the user record in the Privileges dialogue disappears. I had this problem before, but cannot recall how I resolved it.