Try a clear nonvol, it's a bit more comprehensive. On map page tap the Speed field then hold the centre of the Speedometer for several seconds to take you to the hidden 'Diagnostics Page'. Tap 'Developer Info' and scroll down to 'Nonvol Statistics' and tap that. Press the menu symbol [3 bars] in the top LH corner then follow the prompts. This will also reset it to it's 'as new' original settings like a hard reset [master reset] so back up favourites beforehand if you wish.