After installing Fs9.1 patch,PMDG737NG does NOT work anymore :-a message in the red line above, inform me that : "PMDG CG (center of gravity) is OUT of RANGE,airplane is NOT flyble"-EICAS indicators are all at ZERO,included fuel indicators, even if the engines are running-All O/H lights are on-If you try to fly, you crashTHIS IS HAPPENING not just to me,but two people out of five I know,who installed Fs9.1 patch.Mr Randazzo, this is quite serious matter!!!Please try to investigate it ...and find a solution.Thank you very muchRomano ferrari

Mr Ferrari,Well, hundreds of people, and probably more, have upgraded to FS9.1 without a problem. So I think this is a matter of individual set-up/handling matters.One guy who had the problem and posted about it removed the PMDG NG and reinstalled it. The problem was gone.You may also want to check the FS9.1 patch readme file. There are several criteria to a successful upgrade. One of them being updating FSUIPC to latest version 3.40.Hope it helps,

You'll have to reinstall the 737NG package. That's what worked for me... :-roll