The problem is that your computer has not associated the kmz extension with executing Google Earth. If you know how to associate extensions with files, that is your best option. Or ask someone (your computer geek) to help you. Things will be easier in the future. But if not computer savvy, continue below.
If Google Earth is not a listed option, you may do either of two alternates.
- If an 'alternate' option is listed, click your way to the "C:\Program Files". Then click your way down through "Google/Google Earth/client, and in that folder double click on the file "googleearth.exe". Google should open and the track file should shortly be shown.
- If that does not work, or you are not sure on the above, right click and save the kmz file (make sure you know where it is being saved). Then open Google Earth and in the upper left top click on File/Open and point to the saved kmz track file. Google should open and the track file should shortly be shown.