Well, NAV crashes constantly if you do not know how to handle it properly
CF 1.6 Nav is extremely unstable. So if you use visualisations it will crash your GPS the instant you start the vis. If you watch a video clip or DVD that will grash the GPS too. If you enter media manager and the wrong vis is in the preview, that crashes the GPS too, and finally if you have something else on your computer that manages to get the CPU to go to 100% for a sec or more... Then CF crashes the GPS
No need to reeboot everytime this happens, just restart CF and the NAV continues where it left. Too bad there is no option to restart CF, but in the future I hope this will not be an issue at all.