If you want temp users to be able to register and send packages, you must select the second option (All) for Which Users Can Send Packages. If you select the first or third options, the Don't have an account? prompt and Register and Send Files link will not be displayed on the Sign On page. Any settings on the Ad Hoc Transfer - Access - Unregistered Senders page will not be applicable. (An application message will be displayed on the top of that page to inform you that these settings will not be used because Ad Hoc Transfer is disabled. It will say: "Ad Hoc Transfer is not enabled for All users. None of the settings on this page will take effect; to change this, go to the Registered Senders setting page.")