Can not use Spyder 6 with old conda (4.8.3)

[impact27]

Issue Report Checklist

• Searched the issues page for similar reports
• Read the relevant sections of the Spyder Troubleshooting Guide and followed its advice
• Reproduced the issue after updating with conda update spyder (or pip, if not using Anaconda)
• Could not reproduce inside jupyter qtconsole (if console-related)
• Tried basic troubleshooting (if a bug/error)
  • Restarted Spyder
  • Reset preferences with spyder --reset
  • Reinstalled the latest version of Anaconda
  • Tried the other applicable steps from the Troubleshooting Guide
• Completed the Problem Description, Steps to Reproduce and Version sections below

Problem Description

kernel doesn't open when using old version of conda (4.8.3, works with 4.9)

What steps reproduce the problem?

1. Install Spyder 6 with conda 4.8.3
2. Try to use a kernel

What is the expected output? What do you see instead?

Paste Traceback/Error Below (if applicable)

An error occurred while starting the kernel
usage: conda‑script.py [‑h] [‑V] command ...
conda‑script.py: error: unrecognized arguments: ‑‑no‑capture‑output

Versions

• Spyder version: 6.0.0
• Python version: 3.14
• Qt version:
• PyQt version:
• Operating System name/version: windows

[dalthviz]

Hi @impact27 thanks for the report! So probably we need to handle the case of people having older conda versions, right @ccordoba12 @mrclary ? Or maybe at least better detect the error and prompt users to update conda >=4.9 ?

[mrclary]

@impact27, how do you have Python 3.14?
Why would the conda version matter?

[ccordoba12]

Or maybe at least better detect the error and prompt users to update conda >=4.9?

I think this is the only thing we can do because we can't activate envs with conda versions that don't support --no-capture-output. The problem is this:

• We now use conda run to activate envs, instead of the scripts we used before. That mechanism is more robust and better supported upstream by conda.
• @impact27, since you changed receiving the kernel's stdin/stdout streams to pipes, we need a way to let that info pass through the conda run process to get it in Spyder. And that's precisely what --no-capture-output does.

A fix shouldn't be that hard. Just checking that conda‑script.py: error: unrecognized arguments: ‑‑no‑capture‑output is in the kernel error message and change it for another text that is more meaningful.