How to Fix a Conda Environment With Specific Python Version

I recently ran into a tricky situation while trying to set up a Conda environment with a very specific Python version (3.3.0). I thought it would be a simple one-liner, but things didn’t go as planned. Instead of my environment using the right interpreter, I ended up with mismatched Python versions and a broken IPython setup. Let me walk you through exactly what happened, why it broke, and how I fixed it step by step.

The First Attempt Creating The ENV

I started by creating the environment:

# Create the env
conda create -n "myenv" python=3.3.0

# Activate it
conda activate myenv

I expected python to now point to version 3.3.0 inside my Conda environment. But when I checked:

python   # → version 2.7.15 at /usr/bin/python (unexpected!)
ipython  # → Python 3.6.8 at /home/myname/.local/bin/ipython (also unexpected!)

Meanwhile:

python3   # → /home/myname/miniconda3/envs/myenv/bin/python3 (correct)
ipython3  # → Python 3.6.8 again (wrong)

Even reinstalling Python didn’t help:

conda install python=3.3.0  # no change

And trying to start IPython with the env’s interpreter gave me this error:

python3 -m IPython
# → No module named IPython

At this point I was frustrated. But then I discovered something important.

The Breakthrough Use a Minor Version

It turns out the problem doesn’t exist if I specify just the minor version:

conda create -n "myenv" python=3.3 ipython

This gave me Python 3.3.5 and IPython installed in the environment. Both python and ipython now worked exactly as expected.

What Went Wrong

1. PATH order wasn’t applied correctly
   When I ran python, my shell was still picking /usr/bin/python before Conda’s myenv/bin/python. This meant the environment activation didn’t truly “take.”
2. IPython came from outside Conda
   The ipython command was pointing to ~/.local/bin/ipython, which was installed globally with pip --user. It didn’t care about my Conda environment at all.
3. Python 3.3.0 doesn’t exist in Conda channels
   Conda doesn’t keep every micro release. Instead, if you ask for python=3.3, it will install the latest available build for that minor version usually Python 3.3.5.
4. The “No module named IPython” error
   That happened because IPython simply wasn’t installed inside my Conda environment.

The Quick Fix (TL;DR)

# Start fresh with a clear minor spec and include ipython
conda create -n myenv python=3.3 ipython
conda activate myenv

# Verify
which -a python ipython
python -V
ipython --version

Now both python and ipython resolve to paths inside my environment, and versions are consistent.

If You Want to Keep the Old ENV

Sometimes you don’t want to throw away your environment. Here’s how I fixed it in place:

conda activate myenv
echo "$PATH" | tr ':' '\n' | head -5  # env/bin should be first
hash -r                               # clear shell cache
which -a python ipython

If python still points to /usr/bin/python, then re-init Conda:

conda init bash
exec "$SHELL" -l

Then install IPython into the environment:

conda install ipython=5.*
# or if conda fails:
python -m pip install "ipython<6"

Understanding The Error

When I saw:

/home/myname/miniconda3/envs/myenv/bin/python3: No module named IPython

It simply meant: You’re running the right interpreter, but IPython isn’t installed in this environment. Installing IPython there fixes it.

A Clean Build Process

Here’s the final process I now follow for reliable results:

# A) Check what Python 3.3 builds exist
conda search "python=3.3.*" --info

# B) Create the environment
conda create -n myenv python=3.3 ipython

# C) Activate and verify
conda activate myenv
hash -r
which -a python python3 ipython
python -V
ipython --version

# D) Sanity check interpreters
python -c "import sys; print(sys.version); print(sys.executable)"
ipython -c "import sys; print(sys.version); print(sys.executable)"

Practice Functionality: My check_env.py

I even wrote a little script to check if everything is wired correctly:

import sys, sysconfig, platform

print("Python:", sys.version)
print("Executable:", sys.executable)
print("Prefix:", sys.prefix)
print("Base Prefix:", sys.base_prefix)
print("Install Scheme:", sysconfig.get_paths('posix_prefix'))
print("Platform:", platform.platform()

Run it both ways:

python check_env.py
ipython -c "exec(open('check_env.py').read())"

This gives me confidence that both python and ipython are running from the same environment.

Final Thought

In the end, I learned that Conda works best when you specify minor versions (like 3.3) instead of exact micros (3.3.0). Installing IPython inside the environment and checking with simple commands like which and python -V saves a lot of debugging headaches. Now whenever I create an environment, I make sure both python and ipython truly belong to it and I no longer get caught by mismatched versions.