there are a lot of old threads for other models talking about problems with the Columbus head unit. They generally end up talking about an issue that causes the unit to get into a "bootloop" - trying to start up and failing over and over (about every 25 secs) - you can hear the hard drive spin up then - nothing. In my case (Yeti L&K, 4wd, 2014 TDi 140) the screen displays the Skoda Navigation splash, but never gets beyond this - but it varies case to case. There are a number of key combinations you can try to "hard reset" the unit (equivalent to turning it off and on again for a PC). None of them worked for me, but pressing the eject and mic button (top right of the unit) and SETUP causes the following to appear over the splash screen: "The system is not able to start up" and "please insert SWL-CD." (see attached) I have not got any further yet as I can't find anyone who has this file yet. I suggest you try this key press combo and see what happens, and if you get the same message search for the SWL-CD file. I'll let you know if I get to it first