Have tried again. The unzipped gpx file won't go into the GPX folder for the GPS, it bounces out and puts itself at the top of the display of contents. I've cleared all other caches just in case but it makes no difference. Now I'm stuck with a GPS which wont start up when connected to the Mac. The display on the GPS begins and then cuts out so it never connects to the Mac. I have to use the tactic I read somewhere about switching the GPS unit off when it starts to come alive, then switch it back on again, hold the button in for around 30 seconds then it works.