Waiting for extension host

Support Bug Reports
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1

Where does the bug appear (feature/product)?

Cursor IDE

Describe the Bug

The agent/chat does not resepond to me anymore, I only receive waiting for extension host. And due to closing the cursor my ipynb file has crashed which I can’t recover anymore…

Steps to Reproduce

Open a new chat, ask something

Expected Behavior

The agent should talk to me or start implementing changes

Operating System

Windows 10/11

Version Information

Version: 3.0.13 (system setup)
VSCode Version: 1.105.1
Commit: 48a15759f53cd5fc9b5c20936ad7d79847d914b0
Date: 2026-04-07T03:05:17.114Z
Layout: editor
Build Type: Stable
Release Track: Default
Electron: 39.8.1
Chromium: 142.0.7444.265
Node.js: 22.22.1
V8: 14.2.231.22-electron.0
OS: Windows_NT x64 10.0.22631

For AI issues: which model did you use?

All models

Does this stop you from using Cursor

Yes - Cursor is unusable

5

Hey, this is a known issue. The team is aware, and we’re tracking it. A few things to try:

  1. Open a new Agent window Cmd/Ctrl+Shift+P > Open New Agent Window instead of the regular chat. For some users, this unblocked things right away.

  2. Clear the extensions cache. On Windows, delete these folders:

%APPDATA%\Cursor\CachedExtensions
%APPDATA%\Cursor\CachedExtensionVSIXs

Then restart Cursor.

  1. If that doesn’t help, try running from a terminal:
cursor --disable-extensions

If it works like this, one of your extensions is causing the issue.

  1. More drastic option: rename %APPDATA%\Cursor to Cursor_backup and start Cursor again. This resets all settings, but your data will still be in the backup.

About the missing .ipynb file, can you check if it’s still in your project folder? Sometimes the file isn’t deleted, it just doesn’t show up. Also check your git history if the project is under version control.

Let me know if any of this helps.

6

It is beyond annoying that this keeps occurring. Is there any chance this gets fixed in the near future?

7

Hey @Frank_Morales, got it. I can’t give an ETA. “Waiting for extension host” isn’t one bug, it can happen for a few different reasons under the same symptom, so there isn’t one fix. The team is aware and there are tickets.

If you haven’t tried the steps from the post above yet: Waiting for extension host - #5 by deanrie
Start with cursor --disable-extensions and clear %APPDATA%\Cursor\CachedExtensions. Most of the time it’s caused by an extension.

If that doesn’t help, share your Cursor version, your OS, and whether you’re running locally or over SSH or WSL.

8

If it helps anyone, I finally fixed it by changing this in editor settings: “Http: Proxy Support” → Change from override to on