I reinstalled everything.... Visual C++ 2008, PMDG NGX with the latest hotfix and it seems to work so far...I found out that the cockpit of the 737-800 now looks differently... previously my 737-800 cockpits looked like the 737-900 now...So maybe the initial liverymanager intalled the cockpits wrongly ? placing the 737-800 livery in the 737-900 mode ?Anyhow it seems to work now !Regards