Unable to open Jupyter Notebooks: Using the Jupyter notebook editor requires the stable version of VS code and the CustomEditor experiment to be enabled..

Environment data

• VS Code version: 1.51.1
• Extension version (available under the Extensions sidebar): XXX
• Jupyter Extension version (available under the Extensions sidebar): v2020.11.372831992
• OS (Windows | Mac | Linux distro) and version: Win10
• Python and/or Anaconda version: Python 3.8.1
• Type of virtual environment used (N/A | venv | virtualenv | conda | …): N/A
• Jupyter server running: Local and Remote

Expected behaviour

Clicking on a Jupyter-Notebook opens the notebook.

Actual behaviour

Clicking on a Jupyter-Notebook opens the Notebook for a second. Then the file is being closed and the following error is displayed: Unable to open '[*].ipynb': Using the Jupyter notebook editor requires the stable version of VS code and the CustomEditor experiment to be enabled..

This behaviour occurred suddenly, without me changing knowingly anything in VSC. The Notebooks can still be opened on different machines. Furthermore creating a new Notebook works.

Steps to reproduce:

1. Try to open any jupyter notebook within VSC over the side bar -> Leads to error
2. Opening via terminal (code file.ipynb) -> Leads to error

Logs

User belongs to experiment group 'jupyterTest'

[rchiodo]

This shouldn’t be happening but might be caused by this setting being in your user settings.json:

    "workbench.editorAssociations": [
        {
            "viewType": "jupyter.notebook.ipynb",
            "filenamePattern": "*.ipynb"
        }
    ],

Can you check if that editor association is there?

This would likely cause the bug above.

We think you can workaround this bug by:

1. Deleting this section from your user settings.json or
2. Add this additional setting to your settings.json:

    "jupyter.experiments.optInto": [
        "CustomEditor"
    ],

[PeterMakus]

This shouldn’t be happening but might be caused by this setting being in your user settings.json:

    "workbench.editorAssociations": [
        {
            "viewType": "jupyter.notebook.ipynb",
            "filenamePattern": "*.ipynb"
        }
    ],

Can you check if that editor association is there?

This would likely cause the bug above.

We think you can workaround this bug by:

1. Deleting this section from your user settings.json
   or

2. Add this additional setting to your settings.json:

    "jupyter.experiments.optInto": [
        "CustomEditor"
    ],

I experienced exactly the same issue and was able to circumvent the problem by following your instructions. Thanks!