Jupyter IPython - RuntimeError: This event loop is already running

Question

For no particular reason, I've got « RuntimeError: This event loop is already running » when starting Jupyter IPython. I was stucked, unable to run any IPython Notebook. Note that I'm not using Anaconda.

It was probably after updating one library of the Python machine learning ecosystem (Scipy, NumPy, matplotlib, scikit-learn, pandas, Keras, ...) but I cannot remember which one.

I've tried to upgrade the usual suspects, tornado and ipykernel, with no success. Furthermore I'm not using any fancy thing like asyncio in my own code.

Answer 1

After trying many things and probably making the situation worse, I've finally solved the problem.

1) Uninstall IPython

sudo pip3 uninstall -y jupyter jupyter_core jupyter-client jupyter-console notebook qtconsole nbconvert nbformat

2) Reinstall fresh Jupyterlab

sudo pip3 install jupyterlab

Et voilà!