@ LENSMAN01, my 2016 GLC last week has developed the same fault as you experienced. Despite me sharing your experience with my local (NW London) dealership service manager, they are determined to approach this step by step. I am now left waiting until the end of January for the GPS Antenna replacement... It would be greatly appreciated if you have anyone at your local dealership you could put me in contact with to try and speed this up? Happy New Year, MatthewAll fixed. Got a payment from them for the inconvenience and they replace the COMAND system completely. Happy that it's all fixed but not so happy with the reliability in the first place. Anyone had similar issues?