This message alerts the operator that the (optional) Feature Registration Sensor has failed to detect a feature. This may be due to a sensor failure, blockage, incorrect setup, a card feature that is difficult to detect, incorrect amplifier setting (see Section 6.3.2), or a damaged fiber optic. Touch the SET button to open the SET REGISTRATION SENSOR screen. (See Section 6.3.2.) This would be done to check and adjust the registration settings for the material used. Touch the RETURN button to close this screen and open the MAIN screen. If the material was defective, the machine could be cleared of the defective material, loaded with good material, and then restarted.