The j cv folder is your junction view file, leave it alone. You will need to view the very root of the nav drive, if it's not on the sd card, make sure you have hidden files viewable, if there is nothing important on the sd card you could just re format it, but if you installed the osm map on the actual drive of the nav you will need to find it. I have very little knowledge of macs sorry. I will do a search for the info. Do a search on google for JaVaWa. And read through the guides thoroughly.