The Service object always supports the mandatory IADs interface and two COM interface, IADsService and IADsServiceOperations. Service objects that represent File Services also support the IADsContainer interface and the IADsFileService and IADsFileServiceOperations interfaces. The Service object implementation will return E_NOINTERFACE when QueryInterface is called requesting IID_IADsContainer or IID_IADsFileService and the specific service in hand is not a file service.