Multiecuscan

Hi,

I am a registered and happy user of MultiECUscan for several years. I have now run into a problem. I can no longer launch MultiECUscan. The same machine for nearly 2 years without any problems. Last time I used MultiECUscan must have been 3-5 months ago and without issues.

I have collected crash-information and what I already have tried down below.

Any help is appreciated, thank you.

//Morten

___________________________________

Subject
MultiECUScan 5.4 crashes on startup – .NET stack overflow (mscorwks.dll) on Windows 11

Product / Version

Product: MultiECUScan
Version: 5.4.0.0


Operating System

Windows 11 (English UI, fully updated)


Problem Description
MultiECUScan crashes immediately on startup before the UI is shown.
The crash occurs every time and is fully reproducible.
The same version of MultiECUScan previously worked on this exact PC with Windows 11. The issue appeared later without any change to the application itself.

Error Message / Logs
Windows Event Viewer reports an APPCRASH with a .NET runtime stack overflow:

Faulting application: Multiecuscan.exe
Application version: 5.4.0.0
Faulting module: mscorwks.dll
Module version: 2.0.50727.9157
Exception code: 0xc00000fd (STACK_OVERFLOW)
Fault offset: 0x00000000002a395c
Hashed bucket: ce4df82700ff26a62b2454a8830a7378

The crash signature and bucket hash are identical across all attempts.

Steps to Reproduce

Launch Multiecuscan.exe
Application crashes immediately (no UI displayed)


Expected Result
MultiECUScan should start normally and display the main application window.

Actual Result
Application crashes instantly with a .NET Framework stack overflow in mscorwks.dll.

Troubleshooting Already Attempted
The following steps were performed without changing the crash behavior:
.NET / Runtime

Disabled and re‑enabled .NET Framework 3.5 (incl. 2.0 and 3.0) via Windows Features
Verified installation via Windows Update
Forced legacy CLR via Multiecuscan.exe.config:
XML<supportedRuntime version="v2.0.50727"/>Vis flere linjer

Result: no change

File system / permissions

Ran application without administrator rights
Moved installation outside Program Files
Verified UAC virtualization is not involved
Result: no change

User configuration

Reset application data:

%APPDATA%\MultiECUScan
%LOCALAPPDATA%\MultiECUScan


Result: no change

System locale / globalization

Changed System Locale to English (United States)
Ensured “Beta: Use Unicode UTF‑8 for worldwide language support” is disabled
Rebooted
Result: no change

Reinstallation

Clean reinstall of MultiECUScan
Result: no change


Additional Notes

The crash occurs inside the .NET 2.0 CLR (mscorwks.dll) before application logic or UI initialization.
Since the application previously worked on the same system, this appears to be triggered by an OS / .NET servicing update or runtime behavior change rather than a corrupted installation.


Support Request

Is this a known issue with MultiECUScan 5.4 on updated Windows 11 builds?
Are there:

recommended fixes or patches
specific .NET compatibility settings
newer builds addressing this issue
known Windows updates that break startup?

______________________

UPDATE:

Additional troubleshooting performed (update)
Since the previous support submission, we have performed extensive, systematic troubleshooting to isolate the root cause. Below is a concise summary of the additional steps and confirmed findings.

.NET Framework verification

.NET Framework 3.5 (incl. 2.0) is installed via Windows Features.
A custom .NET 2.0 WinForms test application was compiled and executed successfully on the same system.
Result: .NET 2.0 / 3.5 runtime is confirmed fully functional.
The issue is not caused by a broken or missing .NET installation.


User profile isolation

Tested with a new local Windows user account (fresh profile).
MultiECUScan still crashes immediately with the same error.
Result: Not user‑profile related (not HKCU, user cache, or per‑user configuration).


Application reinstallation

MultiECUScan was fully uninstalled and reinstalled.
Application still crashes on startup.
Result: Not a corrupted installation or application files.


FTDI / COM driver verification

Verified via Device Manager:

No FTDI drivers
No USB Serial / COM devices
No ELM or serial drivers installed


MultiECUScan crashes even with no diagnostic cable connected.
Result: Not related to FTDI / COM / USB drivers.


Clean Boot test (system‑wide isolation)

Performed a full clean boot:

All non‑Microsoft services disabled
All startup applications disabled


After reboot, MultiECUScan still crashes with identical behavior.
Result: Not caused by third‑party services, antivirus, EDR, overlays, or injected hooks.


Crash consistency

Crash remains fully reproducible with:

Faulting module: mscorwks.dll
Exception code: 0xc00000fd (STACK_OVERFLOW)


Fault offsets may vary slightly, but the failure mode and timing are unchanged.
Crash occurs before UI initialization.


Technical conclusion (current state)
Based on all performed tests:

The operating system and .NET runtime are confirmed functional.
No user‑level, driver‑level, or service‑level environmental cause remains.
The failure appears to be a low‑level incompatibility between MultiECUScan 5.4 and the current Windows 11 / .NET 2.0 CLR behavior, likely introduced by OS servicing updates.
This is not resolvable via configuration, reinstallation, or environment cleanup on the client side.

Contact MES Support.

I'm on Windows 11 Pro - 25H2 and Windows 11 Home - 25H2 both @ OS Build 2620008037 and all is fine.

Thank you. I will try that. Thought support was here

There was an issue due to Win11 update on ARM processor. Support helped me and it is now working fine.

Thanks to MultiECUscan support for a great support.