A little tip I picked up from my VA Chief that worked like a charm for me. I suddenly started getting CTD and FATAL ERRORS after 2 weeks of flying fine all over the US but suddenly I was FATAL ERRORING while trying to depart Tampa to head back home to Texas. I could not get off the ground. Going through start up checks.. CRASH... Taxing CRASH. Thinking about a steak dinner, CRASH.
This is something you should do frequently, say after every 3 or so long flights. This is considered Basic FSX Maintenance to keep your sim happy and relatively crash free on this type of crash problem.
1. Navigate to your %appdata% folder and go into LOCAL (Not ROAMING). Find your Microsoft folder and your shader folder. Go into the shader folder. Delete the Shader10 and Shader folder if you have them. Be sure you don't PERMANENTLY delete them. Just delete them to your recycle bin. If something screws up you want to be able to restore the files.
2. Navigate to your C: drive to the ProgramData folder. Navigate to your Microsoft and then FSX folder inside the ProgramData folder. Delete the Facilities and SceneIndexes folders. Do not touch any files outside these folders or the SceneryCache folder. Once again, do not permanently delete these files. Leave them in your recycle bin encase you need to restore them.
3. Start FSX and let it rebuild your Facilities, Scene Indexes and Shader folders. Fly! PROFIT.
This little maintenance tip got rid of my CTDs and I was able to come home to Dallas Love in Texas. Hope it helps anyone out that is experiences this type of sudden crashing after your FSX was working fine for days. This type of CTD commonly shows up as D3D11.DLL or StackHash type crashes in Event Viewer/AppCrashViewer.