Jupyter conda tab 'An error occurred while retrieving package information.'

On windows, running conda install -c conda-forge nb_conda_kernels worked for me.

See this issue: https://github.com/Anaconda-Platform/nb_conda/issues/23

The issue seems to be a conflict between the notebook config file in the conda environment and the config file in the users directory.

To fix the issue and get the tab to display properly the content, I had to remove that file:

rm jupyter_notebook_config.json in ~/.jupyter

Note that, for me, that was not an issue as it did not really contain anything.

As pointed out at: https://github.com/Anaconda-Platform/nb_conda/issues/23#issuecomment-239813091

The following command helped in resolving the issue:

jupyter serverextension disable nb_conda
jupyter serverextension enable nb_conda

This basically rewrites the config file in the ~/.jupyter folder.