Is what you are referring to the system freezing on start up, and just showing the 'Citroen' home page. If so its a well documented known issue. My car had the problem the day I took delivery from the dealership.
Since then it will fail to boot up if you usually, although not always, leave the car for a short period of time. The other problem I get, is occasionally theSat Nav voice stops working.
I have found that the problems can be resolved by switching the car off, and sometimes leaving it locked for a few minutes.
There are software updates but they can make things worse, so I have decided to live with it.