I have exactly the same problem with my car. Playing up even before I drove the car away from the dealer when I took delivery. It seems Citroen don't have a definitive answer. In my case my dealer initially proposed removing the entire system and sending it back to Citroen, leaving me with nothing until they replaced it!!!Fortunately another dealer offered to supply a replacement system if investigation showed a fault, and my selling dealer also offered me a courtesy car - a DS5, until a replacement unit arrived. I have decided to live with the issue rather than have the whole dashboard taken apart. It usually plays up if you re-start the car after a shorttime, and I have found that be switching off, and sometimes even locking the car until the dash display and park brake light goes off, will remedy the problem. Occasionally I have had to leave the car for even longer. It seems to be to do with the shut down and boot up process goingwrong. A few times I have also had the voice for the Sat Nav fail, and only by switching off and leaving the caroff for a longer period of time, sort of 20-30 minutes, willthat issue sort itself.
All in all the emyway hasquite a few issues, some beyond even my problems. And don't even get me started on the functionality, which is best described as 'a voyage of discovery'!!In its defence when you fully work out how it all works, and learn how to get round the freezing issue, itdoes have some very clever features, a lot of which are excessed directly from the steering wheel controls, and the navigation display is very clear and comprehensive.
Regards
Keith