Hard-resetting a device restores its factory settings and deletes any data you've added. Essentially a hard reset returns the device to its default condition. If you plan on selling or giving away your TomTom One, you may want to perform a hard reset first to remove your personal data. This also gives the new owner a clean slate to work with. You can access the hard reset option in the TomTom One's menu.
Tap any area of the TomTom One's screen to open the main menu.
Tap the "Change Preferences" button on the main menu selection screen.
Tap the arrow at the bottom of the preferences menu to move to the next page. Tap "Reset Factory Settings." Push "Ok" to confirm. The TomTom One will now cycle on and off to complete the hard reset process.