RE: System.AccessViolationException in .NET 2.0 application



Hi,

I have searched this exception and call stack in internal database and
found 2 reported records with the same error. However, both 2 records are
closed as "can not reproduce".

Based on the call stack, there is an AV exception in the
UnsafeNativeMethods.GetOpenFileName code which wraps Win32 GetOpenFileName
API in comdlg32.dll. So the exception is generated in Win32 side while the
Net exception call stack only shows the managed call stack. It is almost
impossible to find out the root cause without using unmanaged debugging to
dig into GetOpenFileName.

Can you reproduce your customers' problem on your side? If so, please feel
free to provide the sample project. I will help to use the windbg to
perform Win32 debugging to find out which x86 instruction is accessing
invalid memory region. You may send the sample project to me at:
jetan@xxxxxxxxxxxxxxxxxxxx(remove "online.")

Just a guess, since the calling of GetOpenFileName API comes from .Net
Framework code, I would not suspect the code of GetOpenFileName or
parameters passed from .Net. I suspect certain 3rd party software may have
corrupted your memory region or changed the CPU registers, which caused the
CPU to read/write an invalid memory region. You may ask your customer to
turn off any anti-virus softwares and screen translation softwares. These
softwares may inject code/dll into any application memory space for hooking
purpose. A more technical way is listing all the modules/dlls in your
application process in problematic machine to examine if there is any
abnormal module/dll(that is neither Microsoft dlls or your application
dlls). You may ask the customer to download Process Explorer to examine the
dll list:
http://www.microsoft.com/technet/sysinternals/ProcessesAndThreads/ProcessExp
lorer.mspx

Hope this helps.

Best regards,
Jeffrey Tan
Microsoft Online Community Support
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