The Shutdown option powers down the receiver and acts as an on/off button, temporarily turning off all communication between your transmitter and receiver during a sensor session. You will not get sensor glucose readings and it will not extend the life of your sensor. If you use the Shutdown option, you can turn your receiver back on by holding down the center (or Select) button. Give the receiver at least 10 minutes for it to display a reading after it turns back on.
The Stop Sensor option ends a sensor session and will show a red stoplight symbol in the upper right corner of the trend graph. You will not get sensor glucose readings and you must dispose of your sensor if you stop the session.