I did use the App just today and it did work for over an hour without any problems. When this did happen I did not receive any error messages. The app just shuts down and the phone goes back to the home page. I did clear the cache just now after I got home. I am not sure how to force close the app. I am not sure when I will be using the app for navigation again, but if I do have any problems in the future I will let you know.