My Anaconda stopped working all of a sudden

My Anaconda stopped working after I installed some packages for statistics (not entirely sure if it is related), I cannot open Jupyter Notebook or Spyder, I can only open Anaconda navigator from the Anaconda command prompt and once there, if I try to run Jupyter or Spyder I get this error message:

`Traceback (most recent call last): File "C:\ProgramData\Anaconda3\lib\site-packages\jupyterlab_server\server.py", line 20, in from notebook.notebookapp import aliases, flags, NotebookApp as ServerApp File "C:\Users\Jorge87\AppData\Roaming\Python\Python37\site-packages\notebook\notebookapp.py", line 49, in from zmq.eventloop import ioloop File "C:\Users\Jorge87\AppData\Roaming\Python\Python37\site-packages\zmq\__init__.py", line 47, in from zmq import backend File "C:\Users\Jorge87\AppData\Roaming\Python\Python37\site-packages\zmq\backend\__init__.py", line 40, in reraise(*exc_info) File "C:\Users\Jorge87\AppData\Roaming\Python\Python37\site-packages\zmq\utils\sixcerpt.py", line 34, in reraise raise value File "C:\Users\Jorge87\AppData\Roaming\Python\Python37\site-packages\zmq\backend\__init__.py", line 27, in _ns = select_backend(first) File "C:\Users\Jorge87\AppData\Roaming\Python\Python37\site-packages\zmq\backend\select.py", line 28, in select_backend mod = __import__(name, fromlist=public_api) File "C:\Users\Jorge87\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\Jorge87\AppData\Roaming\Python\Python37\site-packages\zmq\backend\cython\__init__.py) During handling of the above exception, another exception occurred: Traceback (most recent call last): File "C:\ProgramData\Anaconda3\Scripts\jupyter-lab-script.py", line 5, in from jupyterlab.labapp import main File "C:\ProgramData\Anaconda3\lib\site-packages\jupyterlab\labapp.py", line 14, in from jupyterlab_server import slugify, WORKSPACE_EXTENSION File "C:\ProgramData\Anaconda3\lib\site-packages\jupyterlab_server\__init__.py", line 4, in from .app import LabServerApp File "C:\ProgramData\Anaconda3\lib\site-packages\jupyterlab_server\app.py", line 9, in from .server import ServerApp File "C:\ProgramData\Anaconda3\lib\site-packages\jupyterlab_server\server.py", line 26, in from jupyter_server.base.handlers import ( # noqa ModuleNotFoundError: No module named 'jupyter_server' ` 

I tried uninstalling Python and installing it again, I tried also uninstalling Anaconda and installing it again but nothing seems to work.

I also tried updating Anaconda and writing the command 'Activate Root' and then 'conda update' as I saw in other solutions in stack overflow but nothing seems to work.

I´m using Windows in case this is relevant.

2 Answers

try to reinstall the jupyter_server module since it is the one that is giving you an error. (I do not know if you are working on the base.)

or try to create a virtual environment and run it without anything else (the version of python you have)

conda create --name envexample python=3.7

There you will know if the base environment is corrupted and not the instances themselves.

or do you have another option to reinstall everything

conda update --all --no-pin --no-channel-priority

install jupyter_server may help

conda install -c conda-forge jupyter_server