There are several reset options for your Dash. These include a hard reset, in the event of a device crash or freeze; and two soft factory reset settings that allow you to reset the Dash settings and either retain all of your personal data such as activity files and workouts, or completely wipe the Dash.
To perform a hard reset: Press and hold the ON/OFF button for 6 seconds. The Dash will power off and can be restarted manually using the power button.
To perform a factory reset: See the Factory Reset instructions under Dash Settings.