Can't create or open Jupyter Notebook with VSC insiders

[aisbergde]

Issue Type: Bug

it is not possible to open or to create a jupyter notebook in the current
Cannot read property 'code' or 'markdown'
in the "normal" VCS jupyter notebooks are working.

Extension version: 2020.12.414227025
VS Code version: Code - Insiders 1.54.0-insider (a699ffaee62010c4634d301da2bbdb7646b8d1da, 2021-02-15T05:17:48.792Z)
OS version: Windows_NT x64 10.0.19041

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-7500U CPU @ 2.70GHz (4 x 2904)
GPU Status	2d_canvas: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on oop_rasterization: enabled opengl: enabled_on protected_video_decode: enabled rasterization: enabled skia_renderer: enabled_on video_decode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled
Load (avg)	undefined
Memory (System)	31.87GB (5.89GB free)
Process Argv	--crash-reporter-id a200e218-da5e-491f-adc2-d0355fa904c7
Screen Reader	no
VM	0%

A/B Experiments

vsliv695:30137379
vsins829:30139715
vsliv368cf:30146710
vsreu685:30147344
python383:30185418
vspor879:30202332
vspor708:30202333
vspor363:30204092
vstry914:30244316
pythonvsdeb440:30224570
pythonvsded773:30223139
pythonvspyt875:30251590
core-portspanel:30233467
coreuntitledfile:30249963
wslfolderdoc:30257224

[joyceerhl]

Hey @aisbergde sorry for the trouble. This is happening because there was a breaking change to the VS Code notebooks API in the latest VS Code Insiders update, and the Jupyter extension team is working on publishing a compatible version of the extension to the marketplace. I apologize for the trouble. In the meantime you can work around this by downgrading VS Code as described in #4796 (comment). Closing this issue as we're tracking the same problem in #4796, please subscribe to that issue for updates.