I have a 788ci HD DI Combo unit that the gps has stopped working on. There was nothing blocking the view of the sky when the gps stopped working. It seems as a result there are no longer any navigation pages showing up in any of the views. Also there is no navigation tab in the main menu. When this happened I had powered the unit up after launching the boat and after approximately 10 min. of waiting it still said there was "No GPS Fix". (The navigation pages were there at this point). I powered the unit down, waited for at least 1 minute then powered the unit back on. At that point I did not see any navigation pages and thus discovered the navigation tab missing from the main menu. I fished for about 3 hrs. and rebooted a couple times but no change. Since then I have updated from version 7.13 to version 7.60 and still no change. I did restore the defaults prior to updating the software.Thanks for your help.