Cursor Freezes when open a cpp (128kb)

Bug Reports
1

Where does the bug appear (feature/product)?

Cursor IDE, cpp view

Describe the Bug

This happens all the time with one specific file which I have been working. The probem is when you try to open a cpp file in the editor.

I opened the Dev Mode and see lots of attempts:

ERR [2056] potential listener LEAK detected, having 7567 listeners already. MOST frequent listener (2820):: Error
at Uuc.create (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:47:12844)
at r_._event [as onDidLayoutChange] (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:49:1650)
at new R9e (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:451:143162)
at new PTn (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6846:450)
at Zx.getZoneWidgets (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6846:19577)
at Zx.showDiff (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6846:20292)
at Zx.showDiffs (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6846:18520)
at lEt.value (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:6846:15608)
at _e._deliver (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:49:2962)
at _e._deliverQueue (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:49:3053)
at e.fire (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:49:3390)
at r.setModel (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:293:711)
at IBn.setInput (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:8456:31822)
at async Lvn.doSetInput (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:2797:28710)
at async Lvn.doOpenEditor (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:2797:26451)
at async Lvn.openEditor (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:2797:25376)
at async vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:2909:33111
at async lEt.value (vscode-file://vscode-app/c:/Users/feder/AppData/Local/Programs/cursor/resources/app/out/vs/workbench/workbench.desktop.main.js:2925:46724)
error @ workbench.desktop.main.js:55
error @ workbench.desktop.main.js:55
error @ workbench.desktop.main.js:9357
handleUnexpectedError @ workbench.desktop.main.js:9354

Steps to Reproduce

Open Cursor AI load file, click on file editor

Expected Behavior

App Freezes

Operating System

Windows 10/11

Current Cursor Version (Menu → About Cursor → Copy)

Version 1.7.40
VS Code 1.99.3

For AI issues: which model did you use?

Sonnet 4

For AI issues: add Request ID with privacy disabled

None

Does this stop you from using Cursor

Yes - Cursor is unusable

2

Updated to 1.7.44.0 and still same issue

3

Hey, thanks for the report. Your logs point to a listener leak in the diff rendering pipeline when opening a specific 128 KB .cpp file, which causes Cursor to freeze.

To help us reproduce and prioritize the issue, please confirm:

  1. Does this happen with other .cpp files or only this one?
  2. Do you have any C/C++ related extensions installed?
  3. Does turning off Cursor AI features help? You can exclude the file via a .cursorignore in the project root:
    your-file-name.cpp
  4. Can you share a minimal sample or file characteristics that trigger the issue?

Quick workarounds:

  • Open Process Explorer Cmd/Ctrl + Shift + P → Developer: Open Process Explorer to check for resource spikes
  • Launch with extensions disabled: cursor --disable-extensions
  • Exclude the file from indexing via .cursorindexingignore

Any extra details that help us reproduce it will speed up a fix.

4

Thanks. For some reason, when I open additional context in the AI Context Window, going back to the faulty context and file fixed it. No freeze no.

I will let you know if any issues.

Thanks

1 Like
5

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