Best thing you can do, get a card reader, hook that up into your computer, check the sd card and make sure that it is blank. Then copy the the original sd card to the new sd card, put the original card away in a safe place and keep it for when you need to reinstall a new sd card. Of course if you don't want to do that then just stick the original sd card into the side of the gps unit and use it till it starts to act up. At which point you will need yet another original sd card from the manufacturer. It's a viscous cycle. Hope this helps