Where does the bug appear (feature/product)? Cursor IDE Describe the Bug Hi Cursor Team, I recently upgraded to Cursor 3 (latest version), and immediately after the update, I started experiencing critical issues with core features. The Problem: Jupyter Notebooks: I am unable to open any .ipynb f…

Hey @Max_Wang , this is a known bug and it’s being tracked, but there’s no specific ETA for a fix yet. For now, the thread has a couple of working workarounds that several users have confirmed: If startup gets stuck on a .ipynb, open Cursor on any other file first, like a .py or .sql, wait until i…

@Sergii-L Unfortunately, chats and agent history from Cursor 3 aren’t compatible with version 2.6.22. They use different state.vscdb formats. If you renamed the %APPDATA%\Cursor folder to Cursor_backup, your v3 data is still there in Cursor_backup. You can switch back to Cursor 3 and rename Cursor_b…

@VasilisT The same symlink fix above might help make the solution stick across restarts. Please try it and let me know if it still works after restarting.

@Shaoyang_Xue The team is aware of this issue. There’s no exact ETA yet, but your reports help with prioritization. If the workaround of disabling the Python Environment extension works for Jupyter, use that for now. Also try the cursor-socket symlink fix above, it may fix the root cause. Let me kn…

Previously, even after disabling the Python Environment extension, I occasionally experienced freezes with both Jupyter and the Agent upon restarting Cursor. You are correct, the out folder was indeed missing in that directory（C:\Program Files\cursor\resources\app\extensions\cursor-socket）. I have …

Have had the same issue since release on my Mac. I kept rolling back to previous version, but eventually it would automatically update to cursor 3 even though I kept clicking “Later” on the update popup. Accidentally found a fix that has worked: When opening Cursor on a ipynb editor, I would get the…

[image] Dean Rie: New-Item -ItemType SymbolicLink -Name "out" -Target "dist" Thank you, I have tried that solution, the out symlink file has been generated, but the issue still exist

Thank you, that trick worked on windows too! It takes some time to load but it worked! A good temporary solution until the issue properly fixed on another version

@deanrie thanks - but it did not work what for me ..

Indeed, it works. Takes some 30s to load but works!! Thanks for discovering and sharing @javidv

This worked for me as well, thank you so much!

[Bug] Jupyter Notebooks & AI Panel broken after upgrading to Cursor 3

Support Bug Reports

Max_Wang (Max Wang) April 27, 2026, 11:46am 45

Please fix the bug ASAP.

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[Bug] Jupyter Notebooks & AI Panel broken after upgrading to Cursor 3

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