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NTDLL problem?

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OK, I am at a loss to determine what is causing this CTD with NTDLL always being the guilty party:



Faulting Application Path: C:\Program Files (x86)\Microsoft Games\Microsoft Flight Simulator X\fsx.exe

Problem signature

Problem Event Name: APPCRASH

Application Name: fsx.exe

Application Version: 10.0.61637.0

Application Timestamp: 46fadb14

Fault Module Name: ntdll.dll

Fault Module Version: 6.1.7601.18229

Fault Module Timestamp: 51fb1072

Exception Code: c0000005

Exception Offset: 0002e41b

OS Version: 6.1.7601.

Locale ID: 1033

Extra information about the problem

LCID: 1033


It seems NTDLL was update on 9/11/13 and the only updates were the following Window updates:


If anyone can give me a clue on what to look for it would be appreciated. At first I thought it was related to Simconnect but after deinstalling add-ons and reflying the same flight plan (different aircraft) and getting the same CTD I eliminated Simconnect as a problem. Could one of the Windows updates be causing many of us the same CTD with NTDLL.DLL?



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Hi Bob!


Fault Tolerant Heap and NTDLL.dll. Heap metadata can become corrupted and it has been identified by Microsoft as one of the most common causes of application failures. When an application crash shows the faulting module as ntdll.dll along with the Memory Access Violation (Exception Code) (0xc0000005), then Windows places the application on a watch list and, if the application crashes at least four times or more in an hour, the fault tolerant heap service will configure the application to use the fault tolerant heap service in the future (Source - Chapter 10, Memory Management, Windows Internals, Part 2: Covering Windows Server 2008 R2 and Windows 7 by Mark E. Russinovich, David A Solomon, and Alex Ionescu). The service is part of the Security Center service.


This happened to me recently when I received ntdll.dll crashes and now this is the type of report I get with the AppCrashView Report:  (FSX does not crash)











Sig[0].Name=Application Name


Sig[1].Name=Application Version


Sig[2].Name=Application TimeStamp


Sig[3].Name=Error Types Mitigated


DynamicSig[1].Name=OS Version


DynamicSig[2].Name=Locale ID






AppName=Microsoft Flight Simulator®

AppPath=C:\Program Files (x86)\Microsoft Games\Microsoft Flight Simulator X\fsx.exe


Based on this report, I'm assuming that Windows has trapped by ntdll.dll errors and I should no longer see them.  So, if you are getting the ntdll.dll crash, try to replicate it several times within an hour (at least 4 times) and the error should go away.  Consider though that the ntdll.dll has a function with memory management and indicates you are have issues with system memory.  It could be a bad overclock or a setting or two in the Fsx.cfg that is too high.  You also want to make sure your Virtual Memory (Page File) is set to System Managed Size.  It works best for FSX.


You can check to make sure the service is running on your system by opening up your Event Viewer, Applications and Services, Microsoft, Windows, Fault Tolerant Heap.


Hope this helps.


Best regards,








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I found that I was having this same problem recently where FSX would CTD with the same error indicating that 'ntdll.dll' was the faulting module. This would happen whenever I fly an aircraft such the PMDG 777 and mid-flight without any warning. Sometimes it could take up to 3-4 hours before the crash would happen.


After some searching I found that it could be related to video memory and took the following actions to try resolve it.


-Updated my nVidia graphics drivers to the latest version (version 327.23)

-Deleted the FSX shaders cache located in 'C:\Users\<username>\AppData\Local\Microsoft\FSX\Shaders' as well as 'Shaders10' folders.

-Removed the following tweak I recently added into my FSX.cfg. Performance difference seems negligible without it.




I did 2 flights in the 777 yesterday totaling 12 hrs without shutting down the sim and no longer got any crashes. I can't exactly pinpoint which of the above actions may have fixed it but I suspect it could be the BUFFERPOOLS tweak.

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Jim and FlyBoy: Thanks.....I think this is my scenario--------after installing the DX10 Scenery Fixer, performance was so good I slide ALL my sliders to the far right. I also discovered, thanks Jim, that my Virtual Memory was NOT being managed by the System (so I changed that). I am in the middle of the same CTD flight (and moving along OK). As soon as it is done I will go back and remove my Poolsize=0. Thanks to both and IF ( LOL) these changes don't work I guess I will be back. :lol:

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Well guys, I made it through the flight and landed at KBAD!! I did NOT make it with just the changes Jim had recommended, and did not hit 4 CTDs within an hour. I did reboot the system after the last CTD and removed the poolsize=0. I did not delete the shader cache but completed the flight. I am stumped as to what the real issue is, but it does seem like a combination of too high of settings and not having the System manage my virtual memory. Thanks again for your suggestions!!

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