Install Jupyter Notebook on Miniconda

This problem has just happened to me as well. My older anaconda environments seem to be working fine but the environments I have created today seem to have this exact issue which throws AttributeError: type object 'IOLoop' has no attribute 'initialized'.

It seems to be because of the latest release of tornado==5.0 which released either today or yesterday. I reverted back to the last stable version i.e. tornado==4.5.3 and it worked.

Here's the solution

pip uninstall tornadopip install tornado==4.5.3

Miniconda is OK but Anaconda is recommend.

I have the same issue and thanks Nitred give the right solution.

It seems that jupyter notebook does not support the tornado 5.0. So downgrade as the following:

pip uninstall tornadopip install tornado==4.5.3

I needed matplotlib in python, and need jupyter working. The package will try to uninstall matplotlib if you uninstall tornado, unless you do a force. But I still need matplotlib, I need that. So I still need to force matplotlib to use the old version of tornado. Turns out I had two tornado versions, one installed by pip, other installed by conda.

Ultimately running these commands got jupyter and matplotlib working again: (Ran it in the conda environment that was broken.)

conda remove tornado --force # keeps matplotlibpip uninstall tornadoconda install tornado=4.5.3

I earlier had used pip to install tensorflow library, which I also need, and maybe it brought along the junky tornado v5, not sure.