Jupyter lab will not start

Question

Jupyter lab quit working and I can't get it started again.
OS : win 10
jupyterlab version : 2.2.8
python version : 3.8
browser : Up-to-date Chrome

The error is that the jupyter-lab window shows but displays is the following : Loading... The loading screen is taking a long time. Would you like to clear the workspace or keep waiting? Keep Waiting -OR- Clear Workspace

If I select "keep waiting" : the jupyter lab window does not activate. If I select "clear workspace" : the jupyter lab window only restarts with the same error message.

The cmd result when I attempt to start jupyter lab :

c:\Users\champ\Python_proj>jupyter lab --port 8889 [W 21:57:09.947 LabApp] Error loading server extension jupyter_nbextensions_configurator
    Traceback (most recent call last):
      File "c:\python\python38\lib\site-packages\notebook\notebookapp.py", line 1670, in init_server_extensions
        mod = importlib.import_module(modulename)
      File "c:\python\python38\lib\importlib\__init__.py", line 127, in import_module
        return _bootstrap._gcd_import(name[level:], package, level)
      File "<frozen importlib._bootstrap>", line 1014, in _gcd_import
      File "<frozen importlib._bootstrap>", line 991, in _find_and_load
      File "<frozen importlib._bootstrap>", line 973, in _find_and_load_unlocked
    ModuleNotFoundError: No module named 'jupyter_nbextensions_configurator' [I 21:57:10.645 LabApp] JupyterLab extension loaded from c:\python\python38\lib\site-packages\jupyterlab [I 21:57:10.645 LabApp] JupyterLab application directory is c:\python\python38\share\jupyter\lab [I 21:57:10.819 LabApp] Serving notebooks from local directory: c:\Users\champ\Python_proj [I 21:57:10.819 LabApp] The Jupyter Notebook is running at: [I 21:57:10.819 LabApp] http://localhost:8889/?token= [I 21:57:10.819 LabApp]  or http://127.0.0.1:8889/?token= [I 21:57:10.819 LabApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation). [C 21:57:10.897 LabApp]

    To access the notebook, open this file in a browser:
        file:///C:/Users/champ/AppData/Roaming/jupyter/runtime/nbserver-3700-open.html
    Or copy and paste one of these URLs:
        http://localhost:8889/?token=
     or http://127.0.0.1:8889/?token= [I 21:57:14.415 LabApp] 301 GET /lab/workspaces/auto-y/?clone (::1)
0.00ms [I 21:57:16.284 LabApp] Build is up to date

I have tried :

1. restarting the OS
2. have uninstalled and reinstalled jupyter lab
3. have run jupyter notebook. Jupyter notebook was running but I could not run any kernels or access any folders.
4. have tried disabling the jupyter_nbextensions_configurator I do not think this is the main issue because I always have this error.
5. I saw that port 8888 is not available so that is why I start it on port 8889. But same error message.

If I can provide more information about the issue please let me know.

Answer 1

You may try jupyter lab --core, it will disable extension

Answer 2

I have reinstalled python3.8 and jupyter. solved