KEPServerEX 5.21.112.0 crashing with ntdll.dll error (0xc0000005) on Windows Server 2012 R2

Question

Hello,

We are experiencing an issue with KEPServerEX v5.21.112.0 on Windows Server 2012 R2.

The program does not operate normally and the KEPServerEX Runtime service fails to start.

In Windows Event Viewer (Application Log)

the following error is recorded: Faulting application name: server_config.exe

Version: 5.21.112.0 Faulting module

name: ntdll.dll Version: 6.3.9600.17415

Exception code: 0xc0000005

Fault offset: 0x000496c5

Application path: C:\Program Files (x86)\Kepware\KEPServerEX 5\server_config.exe

Module path: C:\Windows\System32\ntdll.dll

We have already performed the following troubleshooting steps:

1. Reinstalled Microsoft Visual C++ 2008 SP1 Redistributable (x86) version 9.0.30729.6161
2. Ran sfc /scannow (no integrity violations found)
3. Reinstalled KEPServerEX
4. Manually deleted the folders C:\Program Files (x86)\Kepware C:\ProgramData\Kepware before reinstalling
5. Reset project configuration files

However, the same issue continues to occur.

If there are any recommended troubleshooting steps or known solutions related to the ntdll.dll (0xc0000005) error on Windows Server 2012 R2, we would appreciate your guidance.

Thank you.

Answer 1

Hi sein jo,

The exception code 0xc0000005 indicates an access violation, which often points to compatibility issues between the application and system libraries such as ntdll.dll. Since you’ve already reinstalled Visual C++ redistributables and KEPServerEX itself, the next step is to confirm whether the version of KEPServerEX you are using (v5.21.112.0) is fully supported on Windows Server 2012 R2. Kepware documentation notes that older builds may not be certified for newer patch levels of Server 2012 R2, so upgrading to the latest supported release of KEPServerEX is strongly recommended.

Additionally, ensure that all Windows Server 2012 R2 updates are applied, particularly cumulative updates that include fixes for ntdll.dll. Running DISM /Online /Cleanup-Image /RestoreHealth can also help repair underlying system components beyond what sfc /scannow covers.

If the crash persists, I suggest testing the application under a clean boot environment (disabling non-Microsoft services) to rule out conflicts with third-party software. Antivirus or endpoint protection tools are known to interfere with OPC servers and can cause access violations.

Another useful diagnostic step is to capture a crash dump using Windows Error Reporting or ProcDump, which can help confirm whether the fault lies in KEPServerEX itself or in a dependency. If the dump consistently points to ntdll.dll, this strengthens the case for a compatibility issue rather than a corrupted system file.

In summary, I recommend:

• Upgrading to the latest supported version of KEPServerEX.
• Applying all Windows Server 2012 R2 cumulative updates.
• Running DISM for deeper system repair.
• Testing under clean boot to rule out conflicts.
• Capturing a crash dump for further analysis if needed.

You can try and let me know how it goes. If you find this answer helpful, please consider clicking Accept Answer so I know your concern has been resolved.

Jason