I had this same issue and finally got it fixed!
If you are on an Linux and are using an Arch-based distro with AUR support, simply install the code-features package using:
yay -S code-features
or any AUR helper of your choosing.
On other operating systems, you should do the following:
Open your VSCode's product.json. I do not know where this file is on your operating system, so please do some research.
Look for the following line:
"extensionAllowedProposedApi": [ ...
Add the following entry to that array:
"ms-toolsai.jupyter": ["notebookConcatTextDocument",
"notebookControllerKind", "notebookDebugOptions", "notebookDeprecated",
"notebookEditor", "notebookEditorDecorationType", "notebookEditorEdit",
"notebookMessaging", "notebookMime", "notebookCellExecutionState",
"portsAttributes", "textDocumentNotebook", "quickPickSortByLabel"]
For example, if the line was originally:
"extensionAllowedProposedApi": [ "extension1", "extension2" ]
Then change it to:
"extensionAllowedProposedApi": [ "extension1", "extension2",
"ms-toolsai.jupyter": ["notebookConcatTextDocument",
"notebookControllerKind", "notebookDebugOptions", "notebookDeprecated",
"notebookEditor", "notebookEditorDecorationType", "notebookEditorEdit",
"notebookMessaging", "notebookMime", "notebookCellExecutionState",
"portsAttributes", "textDocumentNotebook", "quickPickSortByLabel"] ]
Note that with the second method, you will need to edit product.json every time you update VSCode.
I had this same issue and finally got it fixed!
If you are on an Linux and are using an Arch-based distro with AUR support, simply install the code-features package using:
yay -S code-features
or any AUR helper of your choosing.
On other operating systems, you should do the following:
Open your VSCode's product.json. I do not know where this file is on your operating system, so please do some research.
Look for the following line:
"extensionAllowedProposedApi": [ ...
Add the following entry to that array:
"ms-toolsai.jupyter": ["notebookConcatTextDocument",
"notebookControllerKind", "notebookDebugOptions", "notebookDeprecated",
"notebookEditor", "notebookEditorDecorationType", "notebookEditorEdit",
"notebookMessaging", "notebookMime", "notebookCellExecutionState",
"portsAttributes", "textDocumentNotebook", "quickPickSortByLabel"]
For example, if the line was originally:
"extensionAllowedProposedApi": [ "extension1", "extension2" ]
Then change it to:
"extensionAllowedProposedApi": [ "extension1", "extension2",
"ms-toolsai.jupyter": ["notebookConcatTextDocument",
"notebookControllerKind", "notebookDebugOptions", "notebookDeprecated",
"notebookEditor", "notebookEditorDecorationType", "notebookEditorEdit",
"notebookMessaging", "notebookMime", "notebookCellExecutionState",
"portsAttributes", "textDocumentNotebook", "quickPickSortByLabel"] ]
Note that with the second method, you will need to edit product.json every time you update VSCode.
Just ran into this today (I'm on MacOS for my work computer). In my case, upgrading to the pre-release version of the Jupyter extension (v2022.5.1001281006) solved it right away.
If you're not an experienced programmer/software engineer, as is the case for me, I suggest trying to upgrade (or roll back) either VS code or the plugin itself before going with your own dev code for the plugin, as with @CAG2 pt2 answer. (Personally, I had trouble finding a 'product.json' file; perhaps you need an insider's build of VS code for that kind of thing [edit]: https://code.visualstudio.com/api/advanced-topics/using-proposed-api, in which case I think you'd be editing 'package.json').
Hey everyone,
I'm running into a persistent issue with the Jupyter extension in VS Code and I'm hoping someone can point me in the right direction.
I'm trying to run a simple Python cell in a .ipynb notebook, but I can't execute anything because the Jupyter extension fails to start. As you can see in the screenshot, I keep getting the error notification: Extension activation failed, run the 'Developer: Toggle Developer Tools' command for more information.
What I've Tried So Far:
-
Reinstalling: I have completely uninstalled and reinstalled the Jupyter extension (and its related dependencies like the Python extension) multiple times.
-
Restarts: I have closed and reopened VS Code, and even restarted my computer.
-
New Environments: I've created fresh virtual environments (using
venv) and installedipykernelwithin them, but the issue persists no matter which interpreter I select. -
Different Files: This happens with any notebook file, even a brand new one with a single
print()statement.
I feel like I'm missing something obvious, but I can't figure out what
I'm trying to open and execute some ipynb files in Code on Arch Linux. Installed Python and Jupyter extensions.
Whenever I try to run code in the ipnyb file, I get this nagging error message for the Jupyter extension saying
Extension activation failed, run the 'Developer: Toggle Developer Tools' command for more information.
I tried switching the interpreter to the default Python 3.10.2 and also the Python 3.9.x installation in the Anaconda custom environment, but still no luck. Any idea how to fix this?
I just had the same issue but downgrading only the Jupyter extension didn't help.
What worked for me were the following versions of Jupyter and Python extensions:
| Extension | Version |
|---|---|
| Jupyter | 2025.7.0 |
| Jupyter Cell Tags | 0.1.9 |
| Jupyter Keymap | 1.1.2 |
| Jupyter Notebook Renderers | 1.3.0 |
| Jupyter Slide Show | 0.1.6 |
| Pylance | 2025.7.1 |
| Python | 2025.7.1 |
| Python Debugger | 2025.10.0 |
| Python Environments | 1.2.0 |
I hope that list helps anyone encountering the problem in the future. It surely would have saved me quite some time.
Updating both my vscode and jupyter version fixed it for me! seems to have been a temporary version incompatibility
You can solve that problem by inserting"enable-proposed-api": ["ms-toolsai.jupyter"] in the start settings of vs code. So press CTRL+ALT+P -> "Preference: Configure Runtime Arguments" then insert the upper line. After that restart vscode.
The solution to add "enable-proposed-api": ["ms-toolsai.jupyter"] to the runtime of vscode didn't work for me on Arch linux. But when I started vscode from the command line using the argument "--enable-proposed-api ms-toolsai.jupyter" the problem was solved. So I created a custom desktop launcher for this:
Fist, copy the desktop launcher to your applications folder
$ cp /usr/share/applications/code-oss.desktop ~/.local/share/applications/.
Then edit the new file:
$ nano ~/.local/share/applications/code-oss.desktop
Now add "--enable-proposed-api ms-toolsai.jupyter" to both of the Exec lines like so:
[Desktop Entry]
Name=Code - OSS
Comment=Code Editing. Redefined.
GenericName=Text Editor
Exec=/usr/bin/code-oss --enable-proposed-api ms-toolsai.jupyter --unity-launch %F
Icon=com.visualstudio.code.oss
Type=Application
StartupNotify=false
StartupWMClass=Code
Categories=TextEditor;Development;IDE;
MimeType=text/plain;application/x-code-oss-workspace;
Actions=new-empty-window;
Keywords=vscode;
[Desktop Action new-empty-window]
Name=New Empty Window
Exec=/usr/bin/code-oss --enable-proposed-api ms-toolsai.jupyter --new-window %F
Icon=com.visualstudio.code.oss
I restarted my computer and the problem was solved.