Also, export all your waypoints to an SD card as they may be erased also. Once the update is installed, put the card back in the slot and they will reload automatically. The updates will most likely change some menu options. For example, the menu option to export waypoints and routes will most likely change if you haven't loaded previous updates. Not a big problem but you may have to look around for the options as a few will no longer match what you have on the CD that came with the unit. Export the waypoints, restore factory defaults, load the software update then reload the waypoints. As TreeBass suggested, write down all your settings as they will be reset to factory defaults.