Python finds module, Jupyter Notebook does not – environment mismatch explained

In a terminal, python imports your package just fine. In Jupyter, the same import gives ModuleNotFoundError. This usually means Jupyter is using a different Python environment from your terminal. Here’s how to fix it.

1. Confirm which Python Jupyter is using

Run this in a notebook cell:

import sys
print(sys.executable)

Then in your terminal:

python -c "import sys; print(sys.executable)"

Compare the two paths. If they’re different, they’re different environments.

2. Install the package in the notebook’s environment

If Jupyter uses a different interpreter, install your package from inside the notebook:

!{sys.executable} -m pip install your-package-name

This ensures it installs into the same environment the kernel is running.

3. Use virtual environments consistently

Create and activate a dedicated environment:

python -m venv .venv
source .venv/bin/activate   # on Windows: .venv\Scripts\activate
pip install notebook

Then start Jupyter from that environment:

python -m notebook

Now your terminal and notebook share the same site-packages.

4. Register your environment as a Jupyter kernel

To make a specific env selectable in Jupyter’s kernel list:

python -m pip install ipykernel
python -m ipykernel install --user --name myenv --display-name "Python (myenv)"

Then switch to it via Kernel → Change kernel → “Python (myenv)”.

5. Capture a stable environment snapshot with NoteCapsule

Once imports work in your notebook, freeze that environment and structure with a Capsule so you or your teammates can reproduce it later.

from notebookcapsule import create_capsule

create_capsule(
    name="env-fixed-notebook",
    notebook_path="notebook.ipynb",
    data_dirs=["./data"],
    base_dir=".",  # project root
)

The Capsule includes a suggested requirements file and environment metadata tied to the working interpreter.