Version 26.4.0 sometimes doesn't recognize Notebooks

Type: Bug

Behaviour

I have a virtual conda environment and opened a Jupyter Notebook.
I noticed that imports don't seem to extend to cells below the cell containing the import. Restarting VS Code did not fix the issue but downgrading to 26.2.0 did fix it.

Steps to reproduce:

Have a Notebook with the following content:

Cell 1:

import pandas as pd

Cell 2:

df = pd.read_csv('some file.csv')

Observe that pd in the second cell stays white and the import in cell 1 is darkened out.

Diagnostic data

Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)

XXX

Extension version: 2026.4.0
VS Code version: Code 1.123.0 (6a44c352bd24569c417e530095901b649960f9f8, 2026-06-03T11:29:03+02:00)
OS version: Darwin arm64 25.5.0
Modes:
Remote OS version: Linux x64 5.15.0-119-generic

Python version (& distribution if applicable, e.g. Anaconda): 3.12.13
Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Conda
Value of the python.languageServer setting: Pylance

User Settings


languageServer: "Pylance"

testing
• pytestArgs: "<placeholder>"
• pytestEnabled: true

Installed Extensions

Extension Name	Extension Id	Version
bash-ide-vscode	mad	1.43.0
claude-code	Ant	2.1.169
cmake	twx	0.0.17
cmake-language-support-vscode	jos	0.0.9
cmake-tools	ms-	1.23.52
cpp-devtools	ms-	0.5.13
cpptools	ms-	1.32.2
datawrangler	ms-	1.24.1
debugpy	ms-	2026.6.0
docker	doc	0.18.0
gitlab-workflow	Git	6.81.0
gitlens	eam	18.0.0
hexeditor	ms-	1.11.1
html-preview-vscode	geo	0.2.5
js-debug	ms-	1.117.0
jsts-chat-features	Typ	0.0.2
jupyter	ms-	2025.9.1
jupyter-renderers	ms-	1.3.0
live-server	ms-	0.4.19
python	ms-	2026.2.0
snakemake-lang	sna	0.8.2
vscode-containers	ms-	2.4.5
vscode-docker	ms-	2.0.0
vscode-dotnet-runtime	ms-	3.0.2
vscode-edit-csv	jan	0.11.9
vscode-js-profile-table	ms-	1.0.10
vscode-jupyter-cell-tags	ms-	0.1.9
vscode-jupyter-slideshow	ms-	0.1.6
vscode-language-pack-de	MS-	1.123.2026060618
vscode-markdownlint	Dav	0.61.2
vscode-pull-request-github	Git	0.146.0
vscode-pylance	ms-	2026.2.1
vscode-xml	red	0.29.3
vscode-yaml	red	1.23.0
vsliveshare	ms-	1.1.122

I can't reproduce the issue reliably but it does happen sometimes to me.

Are you still facing this issue?

Yes, but the symptoms slightly changed: Now the language server doesn't seem to pick up when opening a notebook, i.e. no syntax highlighting for the notebook. The notebook was checked into source control but "dirty". I looked at the logs but I couldn't find anything unusual. However, the issue remains very hard to reproduce and is therefore also hard to pin down to a specific version.

Karthik Nadig (@karthiknadig)

Hey Karthik Nadig (@karthiknadig), this issue might need further attention.

Thomas1664, you can help us out by closing this issue if the problem no longer exists, or adding more information.

Because we have not heard back with the information we requested, we are closing this issue for now. If you are able to provide the info later on, then we will be happy to re-open this issue to pick up where we left off.

Happy Coding!

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Version 26.4.0 sometimes doesn't recognize Notebooks #25999

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Version 26.4.0 sometimes doesn't recognize Notebooks #25999

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Behaviour

Steps to reproduce:

Diagnostic data

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Thomas1664 commented on Jun 9, 2026

eleanorjboyd commented on Jul 2, 2026

Thomas1664 commented on Jul 29, 2026

github-actions commented on Aug 28, 2026

github-actions commented on Sep 28, 2026

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