I've successfully installed MATLink and used it in the past, but for some reason a couple of days ago it stopped working. It's maybe due to a Windows update? The error thrown is the following:

This is after running

Needs["MATLink"]
OpenMATLAB[]


I've rerun regmatlabserver just in case.

Any ideas on what I can try? In the FAQ there is a procedure entry point error, but it's a different kind, and with a .dll found in system32 and not the MATLAB bin\win64 folder.

Bests

Cris

Troubleshooting information:

Anaconda3 package info: https://pastebin.ubuntu.com/p/npmdrfrmT6/

MATLink 1.1 for Windows (Fri 15 Aug 2014)

11.3.0 for Microsoft Windows (64-bit) (March 7, 2018)

Force 32-bit engine: False

System PATH:
C:\Program Files\Wolfram Research\Mathematica\11.3\SystemFiles\Libraries\Windows-x86-64
C:\Program Files\Wolfram Research\Mathematica\11.3\SystemFiles\Libraries\Windows
C:\Program Files\Wolfram Research\Mathematica\11.3\SystemFiles\Kernel\Binaries\Windows-x86-64
C:\Program Files\Wolfram Research\Mathematica\11.3
C:\Program Files\Wolfram Research\Mathematica\11.3\SystemFiles\FrontEnd\Binaries\Windows-x86-64
C:\Program Files\Wolfram Research\Mathematica\11.3\SystemFiles\Kernel\Binaries\Windows-x86-64
C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common
C:\gurobi902\win64\bin
C:\Program Files\ImageMagick-7.0.8-Q16
C:\ffmpeg-4.1.1-win64-static\bin
C:\Program Files (x86)\Common Files\Oracle\Java\javapath
C:\Program Files\Intel\iCLS Client\
C:\WINDOWS\system32
C:\WINDOWS
C:\WINDOWS\System32\Wbem
C:\WINDOWS\System32\WindowsPowerShell\v1.0\
C:\WINDOWS\System32\OpenSSH\
C:\Program Files\MiKTeX 2.9\miktex\bin\x64\
C:\Program Files\Microsoft VS Code\bin
C:\Program Files\gnuplot\bin
C:\Program Files\Git\cmd
C:\WINDOWS\system32
C:\WINDOWS
C:\WINDOWS\System32\Wbem
C:\WINDOWS\System32\WindowsPowerShell\v1.0\
C:\WINDOWS\System32\OpenSSH\
C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL
C:\Program Files\Intel\Intel(R) Management Engine Components\DAL
C:\Program Files\AutoFirma\AutoFirma
C:\Program Files (x86)\Windows Kits\8.1\Windows Performance Toolkit\
C:\Program Files\Mosek\9.1\tools\platform\win64x86\bin
C:\Users\embog\AppData\Local\Programs\Julia\Julia-1.4.0-rc2\bin
C:\Users\embog\csdp6.2.0win64\bin
C:\Program Files\MATLAB\R2020a\runtime\win64
C:\Program Files\MATLAB\R2020a\bin
C:\Users\embog\anaconda3\Library\bin
C:\Users\embog\anaconda3\Scripts
C:\Users\embog\anaconda3
C:\Program Files\MATLAB\R2020a\bin\win64
C:\Users\embog\AppData\Local\Microsoft\WindowsApps
C:\MinGW\bin
C:\Users\embog\AppData\Local\GitHubDesktop\bin
C:\Users\embog\AppData\Local\Microsoft\WindowsApps
C:\Program Files\JetBrains\PyCharm 2019.2.3\bin
C:\Users\embog\AppData\Local\atom\bin

COM server information:

• Try using SetEnvironment within Mathematica to remove everything except Windows and MATLAB-related stuff from the PATH. Check if it works then. Sometimes these issues are caused by an incompatible version of a DLL that ends up loaded. – Szabolcs Aug 23 '20 at 6:50
• Okay, I identified it. The culprit is anaconda3/library/bin. After removing it everything works fine. A couple of days ago I did a conda update -all so the culprit must be one of the updated packages. BUT I notice that if I move C:\Program Files\MATLAB\R2020a\bin\win64 to the beginning of PATH, that is, when I use SetEnvironment the R2020a\bin\win64 is the first directory set, and the I leave all the others as is, then it works well. So I don't need to remove Python from PATH. Do you need any more information? – Cristian Em. Aug 24 '20 at 8:09
The question was answered in the comments to my question by @Szabolcs. In short, move the C:\Program Files\MATLAB\R2020a\bin\win64 to the beginning of PATH using SetEnvironment["PATH"->"C:\\Program Files\\MATLAB\\R2020a\\bin\\win64;[Rest...]"] in Mathematica. The culprit is anaconda3/library/bin, I don't know which package. It is not necessary to remove it from PATH`, just make sure to load the MATLAB folder before that one.