How to fix error "Invalid MEX-file, The specified module could not be found. "

When I try and run a Simulink this error appears, (for simplicity’s sake I have replaced names and locations with placeholders). Both the MEX file, Simulink and any associated MATLAB code were not created by me and I have limited accesses to the inner workings.

Error while obtaining sizes from MEX S-function 'filename' in 'simulink location'.

Caused by:

Invalid MEX-file 'C:\filepath\filename.mexw64': The specified module could not be found.

I have been poking at this for a while now and have tried several recommended actions to resolve this; downloading a complier (MinGW-w64 C), checking file path (the MEX file is definitely present), installing all add-ons and toolboxes I know I need. I've used MATLAB's dependency analyser, and the MEX file isn't showing up even though they are in the folder being analysed. I have also clumsily used a dependency walker, and nothing looks worrisome but I don’t really trust my skill when using it.

The same setup processes has been followed and completed successfully on other devices, without any extra steps. So, I must admit I'm at a bit of a loss here.

If anyone has any advice, I would love to hear it.

[Walter Roberson]

The specified module could not be found typically indicates that a dependancy is unavailable.

[dpb]

Particularly given OP said "Simulink and any associated MATLAB code were not created by me" it's quite possible the mex file was compiled on a different system or with a different compiler/version. If so, it may have dependencies that are incompatible or missing on the OP's system. In that case, recompiling the mex-file on the target system may be the only recourse.

If have Visual Studio, from the Developer command prompt use

dumpbin /dependents "theMEXfile.mexw64"

and check for all dlls and versions thereof. It's a fair bet the original system uses some compiler-installed runtime DLLs that didn't get moved over.

Answer 1

[Chloë]

I have managed to fix this problem for me so I'm just going to outline my steps below so it's all in one place for anyone else with the issue.

first I ran this dependency analyser GitHub - lucasg/Dependencies: A rewrite of the old legacy software "depends.exe" in C# for Windows devs to troubleshoot dll load dependencies issues. (Instead of Dependency Walker (depends.exe) Home Page which was more commonly recommended) This threw less false positives and also had a clearer layout.

This outlined I was missing MSVCR110.dll. My first attempt to get this dll was to install Visual C++ Redistributable and I installed both variants (32-bit and 64-bit) as recommended by other sources but unfortunately this didn't work. I also tried all step located here How To Fix Microsoft Visual C++ DLL Files Missing. Through my research this will likely work for most people but I was still facing the issue.

In the end I took a copy of a friend’s dll via memory stick and manually put that in window/system32 which finally caused my MATLAB code to work. I wouldn’t recommend installing any dlls from any websites.

This took me approximately 3 weeks to sort out so I thought it would be helpful to put all this information in one place for anyone else tearing their hair out like me