Only users and groups handled by the Administrator can be transferred using the "Save Users and Groups" option in 4D. This means that any users or groups created by the Designer will be ignored. Be sure that when you want to transfer group assignments (by saving to a file), none of those groups were created by the designer, otherwise those groups won't be transferred.
Note: Plug-ins Access is also not transferred with the "Save Users and Groups" option because it is not part of user settings; it is a database setting.
For more information on how to use Save Users and Groups, see this Tech Tip: