i was able to delete my Tracks, but can not figure out how to delete all way points at one time. I you tubed it came up with a couple of videos of the HB1198 units and even tho it stays in advanced mode mine does not have the "Delete all NAV data"
You would probably have that setting if the software was current. I had that unit for a short while for demo, but don't remember if that was a choice.
The other way is the go into the Nav menu tab, down to Waypoints, Routes, Tracks and right arrow the 4-way button.
Up arrow to Options then right arrow, then down arrow to choose "Select All and..."
Right arrow to get another menu choice, and select DELETE
It is the same procedure you would go through to EXPORT your nav data to a memory card.