Stack Exchange
Jupyter Notebook not launching (Anaconda)
When I try to launch Jupyter notebook through Anaconda, I get the following error message: 
Traceback (most recent call last):
File "C:\Users\Michael\anaconda3\Scripts\jupyter-notebook-script.py", line 6, in 
from notebook.notebookapp import main
File "C:\Users\Michael\AppData\Roaming\Python\Python37\site-packages\notebook\notebookapp.py", line 49, in 
from zmq.eventloop import ioloop
File "C:\Users\Michael\AppData\Roaming\Python\Python37\site-packages\zmq\__init__.py", line 47, in 
from zmq import backend
File "C:\Users\Michael\AppData\Roaming\Python\Python37\site-packages\zmq\backend\__init__.py", line 40, in 
reraise(*exc_info)
File "C:\Users\Michael\AppData\Roaming\Python\Python37\site-packages\zmq\utils\sixcerpt.py", line 34, in reraise
raise value
File "C:\Users\Michael\AppData\Roaming\Python\Python37\site-packages\zmq\backend\__init__.py", line 27, in 
_ns = select_backend(first)
File "C:\Users\Michael\AppData\Roaming\Python\Python37\site-packages\zmq\backend\select.py", line 28, in select_backend
mod = __import__(name, fromlist=public_api)
File "C:\Users\Michael\AppData\Roaming\Python\Python37\site-packages\zmq\backend\cython\__init__.py", line 6, in 
from . import (constants, error, message, context,
ImportError: cannot import name 'constants' from 'zmq.backend.cython' (C:\Users\Michael\AppData\Roaming\Python\Python37\site-packages\zmq\backend\cython\__init__.py)

How do I go about fixing this? I already tried reinstalling Python and Jupyter (for what it's worth).

Try:
conda uninstall pyzmq
conda install pyzmq

or
pip uninstall pyzmq
pip install pyzmq

source: https://github.com/jupyter/notebook/issues/3435
