What does the error, "fl:filesy​stem:Acces​sDenied" mean when trying to use Python?

I am trying to call Python from MATLAB, but whenever I run any Python commands, I get the error: fl:filesystem:AccessDenied

For example:

>> pyenv

fl:filesystem:AccessDenied

>> py.list({'This','is a','list'})

fl:filesystem:AccessDenied

I can't find any information about what this means.

I have Python 3.9 installed and I can call Python from the Windows command line.

[Manikanta Aditya]

Why do I get an error "mclCopyDir failed: fl:filesystem:AccessDenied Failed to copy user-level MATLAB settings ..."... - MATLAB Answers - MATLAB Central (mathworks.com)

Check this ML answer post, this should fix your issue.

[Matt Butts]

I only have one MATLAB session open and I tried restarting my machine.I am also not getting anything additional for the error so I am not sure this is the same issue.

[Matthias Schwaiger]

The same happens on my machine when editing simulink models (I do not use python). I use a separate prefdir and also a separate temp-folder for that Matlab instance only. Is there any way to see which file can not be accessed in order to track it down?

Answer 1

[Matt Butts]

Using information from here: https://www.mathworks.com/help/matlab/matlab_external/install-supported-python-implementation.html

I explicitly set the version to use and that resolved the issue.

>> pyenv(Version="C:\Users\gk874\AppData\Local\Programs\Python\Python39\pythonw.exe")

ans =

PythonEnvironment with properties:

Version: "3.9"

Executable: "C:\Users\gk874\AppData\Local\Programs\Python\Python39\pythonw.exe"

Library: "C:\Users\gk874\AppData\Local\Programs\Python\Python39\python39.dll"

Home: "C:\Users\gk874\AppData\Local\Programs\Python\Python39"

Status: NotLoaded

ExecutionMode: InProcess

To MathWorks Support, I think this error message could be greatly improved to help a user understand exactly what was happening. I expected MATLAB to find my Python installation directly, but that seems to not be the case.