have you set up any locations like lakes? the default location is My Data, so all you waypionts, routes and tracks are defaulted to My data unless you create another locacion. I do this for every lake I visit so that when I save any type of info it is to that location, then I can just export that location instead of My data. Off track here, but go back into the settings and be be sure that the data in My Data is visible. I did this for one lake and for the life of me could not figure it out. Even had tech support twice, and we upgraded software, reset to factory defaults and nothing. I knew they were there because when starting up the unit and the screen was in map view, I could see the waypoints zoomed out, then they would just disappear after a few seconds. I could still see other waypoints on the lake. I check the settings for that location and sure enough the visibility was turned to off. Don;t know how that happend. But I figured it out while i was on the phone with tech support. They also stated that by resetting to factory defaults it should have made them visible. Was not the case. Try that out.
I have never lost my waypoints from either one of my onix units