Some MMI 2G High systems have the navigation CD locked into the drive and pressing the eject button results in no action. This is becuase the "anti theft" setting has been activated from the dealership to prevent the disc being stolen when the vehicle was originally on the forcourt.
How do I eject the disc?
You will need to contact a VAG specialist garage who has access to a tool such as VCDS to change the setting to remove.
This can be done within the 5F module.