Unable to start Python in Positron

[vjburton]

Hello, I was previously happily using Python in Positron but now cannot start a session. In the terminal I receive the error:

Python 3.11.14 (Conda: environment name) failed to start up (exit code -1066598273)

The process exited abnormally (exit code: 0xc06d007f)
0.00s - Debugger warning: It seems that frozen modules are being used, which may
0.00s - make the debugger miss breakpoints. Please pass -Xfrozen_modules=off
0.00s - to python to disable frozen modules.
0.00s - Note: Debugging will proceed. Set PYDEVD_DISABLE_FILE_VALIDATION=1 to disable this validation.

And a pop up: Console exited unexpectedly. View logs for more info.

When I open the log file it is blank.

I can start base Conda, and I can run my environment in Visual Studio Code (which I have gone back to using for the time being). I have tried making a new environment and that won't start either.

I have tried resetting and reinstalling Positron with no change.

My Positron version is:

Positron Version: 2025.11.0 (user setup) build 234
Code - OSS Version: 1.105.0
Commit: 807acdf
Date: 2025-10-31T23:21:13.588Z
Electron: 37.6.0
Chromium: 138.0.7204.251
Node.js: 22.19.0
V8: 13.8.258.32-electron.0
OS: Windows_NT x64 10.0.22631

What else can I try please? Thanks!

[austin3dickey]

Hey @vjburton, thanks for the post!

I suspect this is the same core issue as #9740 (and #9920 mentioned in that issue) since the exit code and some other symptoms are the same. Would you mind taking a look and adding any additional details to that issue if you agree?

It might be helpful to let us know what packages you installed into the problematic environment. You also mentioned that you've done this successfully in the past. Do you know approximately what Positron version this worked in, if you were using the same conda environments?

[vjburton]

Symptoms are similar.

Here are the packages I had installed:

name:
channels:

• conda-forge
• esri
• defaults
  dependencies:
• python=3.11
• ipykernel
• jupyter
• pandas
• matplotlib
• geopandas
• shapely
• fiona
• arcgis
• pip
• pip:
  • python-dotenv
  • openpyxl

It was working earlier in the week using that environment, but I can't recall if there was an update in between. It happened after I switched between machines to work in the same notebook. It doesn't work on that one either now, which is this version:

Positron Version: 2025.11.0 (system setup) build 234
Code - OSS Version: 1.105.0
Commit: 807acdf
Date: 2025-10-31T23:26:12.742Z
Electron: 37.6.0
Chromium: 138.0.7204.251
Node.js: 22.19.0
V8: 13.8.258.32-electron.0
OS: Windows_NT x64 10.0.26200

[austin3dickey]

Cool, thanks! I put a note in #9740. We'll look into that issue soon.

[austin3dickey]

In the meantime, if you'd like to continue using Positron, creating a virtual environment with python or uv should work.

[vjburton]

Thanks! I will try that, I'm using R as well, and it is nice to use the same software for both rather than having to keep switching.

[kyking077-svg]

hi, I'm having the same problem, but I'm a new student in the coding/developing world. How can I work around this error, in baby steps?

[juliasilge]

A great resource for getting started with installing Python is: https://chendaniely.github.io/python_setup/

That guide shows you how to use pyenv and venv, which is a great way to go. Another option you could experiment with is using uv; that would sort of slot in to replace both pyenv and venv but I am not aware of a detailed step-by-step guide of the same quality for someone just starting out! I'd say to start with Daniel's guide.

[kyking077-svg]

thank you!