Cursor PTY Exhaustion Causing Terminal Failures (macOS)

foxted · February 24, 2026, 9:06pm

I hit a terminal failure in Cursor that looked like:

Error initializing PTY: posix_spawnp failed
Turbo/Next runs failing with:
- failed to openpty: Os { code: 6, message: “Device not configured” }
Sometimes also seeing:
- OSError: out of pty devices

Impact

Integrated terminal became unstable / closed.
pnpm dev failed before app code started.
Eventually reproduced in regular Terminal too (system-wide PTY exhaustion).

Root Cause

Cursor had leaked a large number of orphan terminal helper processes:

cursor-shell processes with ppid=1 (orphaned)
In my case: 254 orphaned cursor-shell processes
Each held a PTY, exhausting available PTYs on macOS

How I Confirmed It

PTY allocation test failed:

python3 -c 'import pty; pty.openpty()' → OSError: out of pty devices

Process check showed many cursor-shell instances:

ps -ax -o pid=,ppid=,comm= | awk '$3=="cursor-shell" && $2==1 {print $1}'

Fix (worked immediately)

Kill orphaned cursor-shell processes:

ps -ax -o pid=,ppid=,comm= | awk '$3=="cursor-shell" && $2==1 {print $1}' | xargs -n 50 kill

After cleanup:

cursor-shell count dropped to 0

PTY allocation worked again:

python3 -c 'import pty; m,s=pty.openpty(); print("openpty ok", m, s)'

pnpm dev could start normally again

Notes

This appears to be a Cursor terminal process leak, not a project code issue.
Restarting Cursor helps, but once PTYs are exhausted, killing orphaned cursor-shell processes is the reliable recovery step.
Reference doc for related terminal failures: VS Code terminal launch troubleshooting

Where does the bug appear (feature/product)?

Cursor IDE
Terminal

Steps to Reproduce

So far, since deleting the open processes, I haven’t seen the issue again, but worried there might be run-away processes left behind.

Expected Behavior
No run-away cursor-shell processes to avoid the issue.

Operating System

MacOS Tahoe

Version Information

Version: 2.6.0-pre.42.patch.0
VSCode Version: 1.105.1
Commit: be8e0b780ec172c1c627782307ab8c09c439d2d0
Date: 2026-02-26T00:18:18.482Z (8 hrs ago)
Build Type: Stable
Release Track: Nightly
Electron: 39.6.0
Chromium: 142.0.7444.265
Node.js: 22.22.0
V8: 14.2.231.22-electron.0
OS: Darwin arm64 25.3.0

Does this stop you from using Cursor?

No - Cursor works, but with this issue prevents me from starting my applications without deleting the run-away cursor-shell processes.

system · February 24, 2026, 9:06pm

Hi there!

We detected that this may be a bug report, so we’ve moved your post to the Bug Reports category.

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Where does the bug appear (feature/product)?

Cursor IDE
Cursor CLI
Background Agent (GitHub, Slack, Web, Linear)
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Operating System

Windows 10/11
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Version Information

For Cursor IDE: Menu → About Cursor → Copy
For Cursor CLI: Run agent about in your terminal

IDE:
Version: 2.xx.x
VSCode Version: 1.105.1
Commit: ......

CLI:
CLI Version 2026.01.17-d239e66

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