This may happen if the display is wet and/or stained. Stains may or may not be invisible. Dried drops of water are sometimes hard to see, but may be causing the unit to react randomly. To solve this issue, simply turn off the TM5, then clean the touch screen with moist cloth and a drop of liquid detergent. Be sure to softly dry the surface – a soft paper towel works great. Turn the power of the TM5 back on and resume cooking. If after cleaning the touch screen the Thermomix continues to have these same issues, it is possible the unit may need repair; call Service at 888-867-9375.