Cursor IDE updates broke Jupyter kernels?

Support Bug Reports
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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

At least when running Jupyter kernels on remote machines via remote-ssh, kernels will suddenly “freeze” and will not restart. I have to kill the remote VM or SLURM job in order to get the kernel running again. This issue has only started occurring after my update to Cursor 2.3.29.

This is a very disruptive issue for anyone using Jupyter kernels in the Cursor IDE.

Steps to Reproduce

jupyter                    1.1.1
jupyter-client             8.6.3
jupyter-console            6.6.3
jupyter-core               5.9.1
jupyter-events             0.12.0
jupyter-lsp                2.3.0
jupyter-server             2.17.0
jupyter-server-terminals   0.5.3
jupyterlab                 4.5.0
jupyterlab-pygments        0.3.0
jupyterlab-server          2.28.0
jupyterlab-widgets         3.0.16

Expected Behavior

Jupyter kernels not freezing, and restart should “unfreeze” the kernels.

Operating System

MacOS

Current Cursor Version (Menu → About Cursor → Copy)

Version: 2.3.29 (Universal)
VSCode Version: 1.105.1
Commit: 4ca9b38c6c97d4243bf0c61e51426667cb964bd0
Date: 2026-01-08T00:34:49.798Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin arm64 25.1.0

Does this stop you from using Cursor

Sometimes - I can sometimes use Cursor

4

Hey, thanks for the report.

This looks like an extensions issue in a Remote SSH environment after updating to 2.3.x. In 2.3 we made changes to extension processes, and that caused a few similar issues with SSH connections.

To help with debugging, can you share:

  1. The Jupyter extension version installed on the remote machine (Cmd + Shift + X, search for Jupyter)
  2. The Remote SSH extension version (should be 1.0.37 or newer)
  3. The remote machine OS (Linux distro and version)
  4. Logs from the Developer Tools Console (Cmd + Shift + I, Console tab) when the kernel freezes
  5. The full list of extensions in the remote environment

Temporary workaround: try reconnecting to the SSH host or restarting Cursor.

5
  1. 2025.4.1
  2. 0.113.1
  3. Ubuntu 22.04.5 LTS
  4. Not freezing now, but I’ll post the logs when a kernel freezes again

5) Extensions List:

  • anthropic.claude-code - Claude Code extension

  • anysphere.cursorpyright - Cursor’s Pyright language server

  • charliermarsh.ruff - Ruff linter and formatter

  • mechatroner.rainbow-csv - Rainbow CSV for CSV file visualization

  • mermaidchart.vscode-mermaid-chart - Mermaid chart support

  • ms-azuretools.vscode-docker - Docker extension

  • ms-python.black-formatter - Black code formatter

  • ms-python.debugpy - Python debugger

  • ms-python.python - Python language support

  • ms-toolsai.jupyter - Jupyter notebook support

  • ms-toolsai.jupyter-keymap - Jupyter keybindings

  • ms-toolsai.jupyter-renderers - Jupyter renderers

  • ms-toolsai.vscode-jupyter-cell-tags - Jupyter cell tags

  • ms-toolsai.vscode-jupyter-slideshow - Jupyter slideshow

  • nextflow.nextflow - Nextflow language support

  • openai.chatgpt - ChatGPT extension

  • tht13.html-preview-vscode - HTML preview

7

Thanks for the extra info.

I noticed you’re on Remote SSH 0.113.1. Version 1.0.38 was released recently and fixes SSH connection issues after the extension process changes in 2.3.

Can you update Remote SSH to the latest version? In Cursor: Extensions → search for “Anysphere Remote SSH” → Update.

If the kernel hang happens again after updating, please share:

  • Logs from Developer Tools Console at the moment it hangs
  • Logs from the “Remote - SSH” tab in the Output panel

Let me know if this helps, or if the kernel hangs again.

8

Thanks! I didn’t realize that there was a different remote ssh extension. I uninstalled the old extension and installed the Anysphere Remote SSH extension. However, the extension failed to install the server within the timeout:

```
2026-01-10 08:40:02.519 [info] (ssh_tunnel) stderr:

cursor-server-3c61f 99%[==================> ] 72.93M 3.83MB/s eta 1s

2026-01-10 08:40:02.694 [info] (ssh_tunnel) stderr:

cursor-server-3c61f 100%[===================>] 73.40M 3.74MB/s in 19s

2026-01-10 08:40:02.761 [info] (ssh_tunnel) stdout: Extracting server contents from cursor-server-3c61fc9a-428b-496e-8e5e-c53160c765f4.tar.gz

2026-01-10 08:40:02.761 [info] (ssh_tunnel) stderr: 2026-01-10 08:40:02 (3.87 MB/s) - ‘cursor-server-3c61fc9a-428b-496e-8e5e-c53160c765f4.tar.gz’ saved [76967442/76967442]

2026-01-10 08:40:32.766 [error] Error installing server: Failed to install server within the timeout
```

As far as I can tell, the 30 second timeout cannot be modified. This is a problem for users connecting to servers with slow file systems.

I was able to connect to the remote server after multiple attempts, but it would be great if the timeout was extended or at least modifiable.

10

Great that you’ve updated to Anysphere Remote SSH.

The timeout issue can be fixed with a setting. In Settings CMD+, add:

"remote.SSH.connectTimeout": 300

This increases the timeout from 30 to 300 seconds. Users with slower file systems have been able to connect with timeouts of 180 to 300.

After changing it, try reconnecting to the server.

Let me know if this helped, or if the Jupyter kernel freezing issue shows up again.

11

Thanks for pointing out the timeout setting!

1 Like
12

The kernels are still freezing. I’ll run a cell with other cells in the queue, and the kernel stalls on the first cell, with the Go To button showing activity, but the target cell job has completed and returned output.

I have to restart the kernel and lose all progress, as a result of this issue. The issue is stochastic.

This just opens the agent side panel, so I can’t provide a log.

Cursor

Version: 2.3.35 (Universal)
VSCode Version: 1.105.1
Commit: cf8353edc265f5e46b798bfb276861d0bf3bf120
Date: 2026-01-13T07:39:18.564Z
Electron: 37.7.0
Chromium: 138.0.7204.251
Node.js: 22.20.0
V8: 13.8.258.32-electron.0
OS: Darwin arm64 25.1.0

Remote ssh

Version: 1.0.38

Jupyter

jupyter                    1.1.1
jupyter-client             8.6.3
jupyter-console            6.6.3
jupyter-core               5.9.1
jupyter-events             0.12.0
jupyter-lsp                2.3.0
jupyter-server             2.17.0
jupyter-server-terminals   0.5.3
jupyterlab                 4.5.0
jupyterlab-pygments        0.3.0
jupyterlab-server          2.28.0
jupyterlab-widgets         3.0.16

Remote system

OS: Ubuntu 22.04.5

14

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