Hello,Thanks for helping me out with this error message.DescriptionI have no idea what it is, it is the first time ever I see this error alert.Description:777 united flight KORD ZSPD at about 2/3 of the trip today and over PANC yesterdayTitle of the opening window: Microsoft visual C++ debug librarydebug librarydebug assertion failedprog: Dprogram files...FS9.EXEfile: fprintf.Cline: 56expression: STR!=NULLIf ever one of you have any idea what it is, let me know, started to happen yesterday with 777.the window error allows me 3 option:disregard, fs keep working but the error comes back all the time (every 10 to 30 seconds)Debug, same as aboveTry again, leads to a crash systematicaly.A little hint, in "folder options" "open folder's window in a different processus" was checked, and when i unchecked it while fs was still running, it leads to an fs9 crash.Also the event observer journal traced 2 errors: one unknown and one where fsnav.dll would be the culprit... Cyrille de LattreAsus P4P800/PIV 3 Ghz/2 Giga DDRAMATI X800 GT 256 MegWin XP SP2 / FS9.1 PSS Beta tester

Any one?Cyrille de LattreAsus P4P800/PIV 3 Ghz/2 Giga DDRAMATI X800 GT 256 MegWin XP SP2 / FS9.1 PSS Beta tester

I know what the message means, but not why it occurs. The error is the result of bad passed parameter in one of the running libraries resulting in a bad call to, or from, the fsnav.dll libraries. Since fsnav.dll is not a part of the FS9 modules or libraries it must be either used by the 777 or (more likely) one of your add-ons.DJ

>Any one?>>Cyrille de Lattre>>Asus P4P800/PIV 3 Ghz/2 Giga DDRAM>ATI X800 GT 256 Meg>Win XP SP2 / FS9.1 >PSS Beta testerLooks like a null value wich the program can't handle (so maybe to post in the PSS beta forum?) error handling should take care of this one ;-)Have fun,Andr

Thanks for the replyCyrille de LattreAsus P4P800/PIV 3 Ghz/2 Giga DDRAMATI X800 GT 256 MegWin XP SP2 / FS9.1 PSS Beta tester