After a recent update to the cursor 2.5.25, I cannot select the kernel in Jupyter Notebook. It says “select kernel,” then keeps loading, and after so long, it shows nothing. It can not load previous chat history as well as now, and running .ipynb files have been an absolute mess.
To look into this, I tried to downgrade to the 2.3.35 version as well, which looks like a stable cursor version; it prompts the same error and can not load kernels. The project opens fine in Visual Studio, and I can run the Jupyter Notebook. No issue there whatsoever!
Steps to Reproduce
Install 2.5.25 or 2.3.35 and see if its same issue? Not sure!
Since the issue still happens on 2.3.35 after rolling back, it sounds like some user or extension data got corrupted during the update. A rollback doesn’t always fully reset everything.
A few things to try:
Reinstall the Jupyter extension: Uninstall it completely, restart Cursor, then install it again. This should reset cached kernel paths.
Clear the Jupyter extension storage: Delete this folder, then restart Cursor: %APPDATA%\Cursor\User\globalStorage\ms-toolsai.jupyter
Check for extension conflicts: Run cursor --disable-extensions, then install only the Jupyter extension and test.
Also, could you share:
The Jupyter extension version you’re using (Ctrl+Shift+X, search for “Jupyter”)
The output from the Jupyter output channel (Ctrl+Shift+U then pick “Jupyter” in the dropdown). Do you see any errors?
Since it works fine in VS Code, this is most likely related to the extension state in Cursor. Let me know what you find.
