APP.DLL crash and KB5025221

[Epic7]

Ohh yeah 
its sad to see microsoft not give enough importance to this issue 
well ill have to downgrade then 
 

[airernie]

3 hours ago, Epic7 said:

Ohh yeah 
its sad to see microsoft not give enough importance to this issue 
well ill have to downgrade then 
 

Here's a link to the OS the person I was talking to sent me if you're interested;  https://atlasos.net/

 

Edited November 11, 2023 by airernie

[Epic7]

Yes sir using this one 
but dont install the latest windows 10 22h2 october build with 
instead use a build from march that is before aprill 11 update 
i installed that march build then atlas os for performance 
as when i used atlas os with 22h2 oct build it gave api dll 

[SteveFx]

I have investigated this issue and can report some findings.   I believe that the crash requires a SIMconnect client to trigger it.  
I think that (possibly because of the mentioned Windows Update) something subtle has changed in the behaviour of named pipes causing FSX to get a spurious event that it fails to handle properly.

My suggestion of a possible workaround ( I am uncertain how well this will work) is  therefore to force the use of IPv4 for SimConnect.

With Acceleration or FSX-SE that is as simple as placing the following 3 line simconnect.cfg in your Documents folder.

[SimConnect]
Protocol=IPv4
Address=127.0.0.1
 
Do NOT add a "Port=" line.

With SP2 you need to follow the SDK manual (which is wrong for FSX-SE and acceleration) and additionally craft a simconnect.xml which goes in the same location as your fsx.cfg file.  For SP2 the IPv4 entries in the two files must contain a "Port=" and they must be the same port.

The fsx function that crashes at 3afa2 (Acceleration) or 1ddc (Steam) can be identified as a fileiocompletion callback (ie async IO).   It appears to be used just for reading commands via SimConnect - although it could have other uses that I have not seen. 

The callback receives three parameters - an errorcode, the number of bytes read and a pointer to some "context" setup by FSX earlier.    In normal operation it is called when a SimConnect command is received with an errorcode of zero, the length of the command and the "context".  When a SimConnect client disconnects it is called with an error of  8000014B  aka NT_STATUS_PIPE_BROKEN.

In the failure case it seems to get an errorcode of zero, zero bytes read, but the real issue is that  the "context" pointer is not correct.   The function crashes trying to call a object in the context which isn't there.

[Mattie941]

On 12/6/2023 at 10:26 AM, SteveFx said:

With Acceleration or FSX-SE that is as simple as placing the following 3 line simconnect.cfg in your Documents folder.

[SimConnect]
Protocol=IPv4
Address=127.0.0.1
 
Do NOT add a "Port=" line.

Hi - I'm just trying to find a fix for this myself and thought I'd give your recommendation a go.

What do you mean my the documents folder? Is this the folder where FSX save files are stored? Or do you mean the FSX root folder?

[SteveFx]

It’s your windows  documents folder.
 

C:\users\{your name}\documents. 

[Mattie941]

Thanks. This seems to have fixed my CTDs

[Morgplane]

Hi,

I have been having this same issue for a while now and I have tried the above fix and it has not solved it. Just to confirm, the simconnect.cfg should be in my Windows Documents folder. I also have the same file in my FSX directory and have also applied the fix to that one also.

Thanks,
Morgan