I had this problem, and others of similiar nature until I upgraded my video card. Prior I had frequent freezes which were only partially cured when I reduced the number of tracks that load on startup. At one time I suspected a corrupted ini file, but it turned out that was not the problem, although replacing appeared to work, only because it reset the gpx files it loaded.
Was it worth a new video card, even though the other programs I used worked OK with the old one?
You bet! I think Topofusion is absolutely *amazing* running  with adequate computing horsepower.
Larry