Problem launching jupyter lab - application launch error

Hello everyone, I am new to the site. Your site is great.

I have anaconda navigator 2.4.0.
I also have JupiterLab 3.5.3

I can no longer open JupiterLab.
I have this error message;
Application launch error
Traceback (most recent call last):
File “C:\Users\antho\anaconda3\Scripts\”, line 6, in
from jupyterlab.labapp import main
File “C:\Users\antho\anaconda3\lib\site-packages\jupyterlab\”, line 13, in
from jupyter_server.serverapp import flags
File “C:\Users\antho\anaconda3\lib\site-packages\jupyter_server\”, line 64, in
from nbformat.sign import NotebookNotary
File “C:\Users\antho\AppData\Roaming\Python\Python310\site-packages\”, line 14, in
from . import v1
File “C:\Users\antho\AppData\Roaming\Python\Python310\site-packages\nbformat\”, line 19, in
from .nbjson import reads as reads_json, writes as writes_json
File “C:\Users\antho\AppData\Roaming\Python\Python310\site-packages\nbformat\v1\”, line 19, in
from base64 import encodestring
ImportError: cannot import name ‘encodestring’ from ‘base64’ (C:\Users\antho\anaconda3\lib\

I do not know what to do ?
I have already reinstalled anaconda, jupiterLab…

Do you have any idea for me ? Thank’s you advance !!


Thanks for reaching out, It seems that something went bad in the installation process, let’s try a reinstallation but with a full cleaning process this time:

Full Uninstall

A full uninstall removes all traces of the configuration files and directories from Anaconda and its programs with the anaconda-clean program.

  1. In Windows, open Anaconda Prompt. In Mac or Linux, open your terminal application.
  2. Install the anaconda-clean package:

conda install anaconda-clean

  1. Then, run anaconda-clean. Run the command by itself to remove all Anaconda-related files and directories with a confirmation prompt before deleting each one, or use the --yes argument to remove all those files and directories without being asked to confirm each one.

If you want to confirm each file and directory you are deleting


If you don’t want to be asked about each file and directory

anaconda-clean --yes

  1. anaconda-clean creates a backup of all files and directories that might be removed in a folder named .anaconda_backup in your home directory. Also note that anaconda-clean leaves your data files in the AnacondaProjects directory untouched.
  • After using anaconda-clean, follow the instructions in Simple remove to finish uninstalling Anaconda Distribution.
  1. Open the file explorer.
  2. Delete your environment (anaconda3\envs) and package (anaconda3\pkgs) folders in your user folder.
  3. Open Add or remove programs and uninstall your Anaconda installation or your version of Python.

After that you can reinstall Anaconda again and the problem should be fixed, let us know if it worked, we are eager to help.