Jupyter Server Not Found with Python 3.6.4 through pyenv

Hi, I am able to launch jupyterlab from the command line but unable to do it through the app. I receive:

We were unable to launch a Jupyter server, which is a prerequisite for JupyterLab Native. If Jupyter is already installed, but it is not in your PATH, specify its location below. Otherwise, try installing or updating Jupyter. The Jupyter notebook version must be 4.3.0 or greater.

My package versions are the following:

jupyter==1.0.0
jupyter-client==5.2.2
jupyter-console==5.2.0
jupyter-core==4.4.0
jupyterlab==0.31.5
jupyterlab-launcher==0.10.3
notebook==5.4.0

I use pyenv and jupyterlab is available through the PATH variable (I checked on the cli).

I am on MacOS 10.13.2 (17C205).

Thanks, Francesco

[declanvk]

@klonuo We don’t yet have a new version of the binary for the latest release of jupyterlab, so in the meantime the old binary will be broken. I would recommend build the development version in the meantime.

I’m closing this issue, but feel free to reopen if the development version is broken for you or for any other related reason.

[olgabot]

Hello, I’m having a similar issue where neither Notebook nor Lab will load. Lab will give the below error, and a fix is below for people who are running into the same problems:

 Fri  9 Aug - 06:02  ~ 
  /home/olga/anaconda/bin/jupyter lab --port 8877 --no-browser
[I 06:03:00.343 LabApp] [nb_conda_kernels] enabled, 8 kernels found
[I 06:03:00.522 LabApp] JupyterLab extension loaded from /home/olga/miniconda3/lib/python3.6/site-packages/jupyterlab
[I 06:03:00.522 LabApp] JupyterLab application directory is /home/olga/miniconda3/share/jupyter/lab
[I 06:03:00.524 LabApp] Serving notebooks from local directory: /home/olga
[I 06:03:00.524 LabApp] The Jupyter Notebook is running at:
[I 06:03:00.524 LabApp] http://localhost:8877/?token=c1212a5cea7d8dfc841ac45c01efb9d2fd644466e1ddc381
[I 06:03:00.524 LabApp]  or http://127.0.0.1:8877/?token=c1212a5cea7d8dfc841ac45c01efb9d2fd644466e1ddc381
[I 06:03:00.524 LabApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[C 06:03:00.528 LabApp]

        file:///run/user/1004/jupyter/nbserver-111683-open.html
    Or copy and paste one of these URLs:
        http://localhost:8877/?token=c1212a5cea7d8dfc841ac45c01efb9d2fd644466e1ddc381
     or http://127.0.0.1:8877/?token=c1212a5cea7d8dfc841ac45c01efb9d2fd644466e1ddc381

The loading screen is taking a long time. Would you like to clear the workspace or keep waiting?

For some reason, I’m not able to Ctrl-C either of these processes and have to kill -9 them.

The fix!

FYI the fix was uninstalling everything related to Jupyter and reinstalling…

pip uninstall juptyer jupyterlab
conda uninstall --yes jupyter jupyterlab
conda install --yes jupyter jupyterlab
===