Cameron Thanks for the reply which I found very interesting, but can you tell me what systems Gizmo is required for, as without it the aircraft seems to perform without any problems. I must admit that I have not tried operating from cold and dark yet but have done several successful flights of about one and a half hours duration using the programmed FMC anf ILS, without sim crashes. Also since removing Gizmo have not had one display failure on sim start with the CRJ Please don't think I am doubting your knowledge and experience on this subject but am baffled as to why removing Gizmo seems to get around the problem, for me anyway. I thought that memory exhaustion caused sim crashes and certainly before updating my system had experienced this with other aircraft and situations, which has not been the case with the new system. I will try re-installing Gizmo and see what the effect is. As previously mentioned I have found that on re-installation of Gizmo the displays continue to operate after two or three sim starts then fail. As I have said please don't think there is any criticism intended in my reply, just curiosity, as I have learned to live with the, now minor problem. I will be interested to see what happens with 64 bit X-Plane so I can fully utilise my PC. John