Attempting to plot with matplotlib crashes python console

[brettmelbourne]

I'm teaching a class with mixed OS users. On multiple windows machines with Windows 10 or 11, with Python and matplotlib installed in a Conda environment (latest miniconda), attempting to make a plot with matplotlib crashes the python console. Minimal example:

import matplotlib.pyplot as plt
plt.figure()

or

import matplotlib.pyplot as plt
x = [1,2,3]
y = [4,5,6]
plt.plot(x, y)

Two separate error messages pop up.

• Console exited unexpectedly. View logs for more info. Source: Python
• Python 3.13.7 (Conda: ds4e) exited unexpectedly and was automatically restarted. You may have lost unsaved work. Exit code: -1066598273

The mentioned logs appear to be empty.

We see the same on python 3.13.5, 3.13.7, 3.14.x.

It works just fine on MacOS or Linux.

Positron Version: 2025.09.0 (system setup) build 139
Code - OSS Version: 1.103.0
Commit: 30e3d0a
Date: 2025-08-29T18:46:05.223Z
Electron: 37.2.3
Chromium: 138.0.7204.100
Node.js: 22.17.0
V8: 13.8.500258-electron.0
OS: Windows_NT x64 10.0.19045

[juliasilge]

This looks related to #9740. We haven't been able to reproduce this problem so far, unfortunately. Do you have the set of instructions you give to students to create an environment so that we could try that?

Have you had the students try a regular venv or a venv managed by uv or pyenv? Does that also crash?

[brettmelbourne]

Thanks for following up! Setup is super simple, nothing fancy. Positron setup is vanilla. Miniconda is vanilla. I have replicated the issue students are seeing on a windows 10 VM (students are on Win11).

conda create -n ds4e
conda activate ds4e
conda install python=3.13.7 numpy matplotlib -c conda-forge

Numpy works in that conda environment.

I have tried VSCode on the windows VM with jupyter extension and matplotlib plotting works there in the same conda environment that fails in Positron.

[brettmelbourne]

A regular venv with pip install matplotlib works.

[juliasilge]

Thank you so much! I added your details to #9740 and moved that along to triage.

[brettmelbourne]

Thanks, let me know if I can help