The dreded day has arrived and the change to a new laptop. I downloaded the 50071 from the website and then the win 8 driverss but failure to run. Under device manager , my radar box showed under "other devices". I clicked to update drivers but the following message appeared ". Failure to update due to the hash for the file is not present in the specified catalogue file.. I am using an acer e1-572 laptop with windows 8.1 installed. Tried wiping out air nav and reinstalling and both drives, certified windows and airnav 8 drivers for same message. Any clues what to do next ?