Where does the bug appear (feature/product)?
Cursor IDE
Describe the Bug
Environment
- macOS Version: 26.1 (Build 25B78)
- Cursor Version: 2.1.0-pre.18.patch.0 (Nightly)
- Electron Version: 37.7.0
- Hardware: Multiple Macs (both Intel and Apple Silicon tested)
- Systems Affected:
- sugarbear (hardware)
- taurus (Parallels VM on sugarbear)
Problem Description
Cursor is completely unusable on macOS 26.1. The extension host repeatedly crashes with code 5, making all AI features non-functional. This occurs even with the nightly build that includes Electron 37.7.0 (which should have the macOS 26 Electron bug fixes).
Error Messages
From logs (~/Library/Application Support/Cursor/logs/*/main.log):
[error] [UtilityProcess id: 1, type: extensionHost, pid: XXXXX]: crashed with code 5 and reason 'crashed'
This error repeats every time the extension host attempts to start.
Steps to Reproduce
- Install Cursor 2.1.0-pre.18.patch.0 (nightly) on macOS 26.1
- Launch Cursor
- Attempt to use any AI feature (chat, agent, tab completion)
- Extension host crashes within seconds
- Cycle repeats indefinitely
What We’ve Tried (All Failed)
- ✗ GPU Compositing Disabled:
open -a Cursor --args --disable-gpu-compositing - ✗ Additional Electron Flags:
--disable-gpu --disable-software-rasterizer --js-flags="--max-old-space-size=4096" - ✗ Environment Variable:
launchctl setenv CHROME_HEADLESS "" - ✗ Cleared Application Data: Deleted
~/Library/Application Support/Cursor/and~/Library/Caches/Cursor/ - ✗ DNS Configuration: Fixed Tailscale DNS issues (see below)
- ✗ Fresh Install: Completely uninstalled and reinstalled nightly build
Related Issue: DNS Configuration (Resolved)
We also discovered a DNS issue where Tailscale MagicDNS was forwarding to local router DNS that filtered modern DNS record types. This was resolved by:
tailscale up --accept-dns=false --accept-routes
This ensures systems use Cloudflare DNS (1.1.1.1) directly. However, fixing DNS did not resolve the extension host crashes.
System Configuration
DNS Setup (after fix):
resolver #1
nameserver[0] : 1.1.1.1
nameserver[1] : 1.0.0.1
Cursor Installation:
- Standard installation via DMG
- No custom configurations or modifications
- No firewall blocking Cursor
Comparison with Working Systems
Working: macOS 15.7.1 (Sequoia) - Cursor works perfectly
Broken: macOS 26.1 (Tahoe) - Extension host crashes
Expected vs Actual Behavior
Expected: Based on forum posts, the nightly build with Electron 37.7.0 should work on macOS 26.x after the GPU/lag fixes.
Actual: While the Electron GPU bug appears to be fixed (no excessive lag), extension host crashes make Cursor completely non-functional.
Additional Notes
- The Electron bug fix (addressed in v36.9.2+) resolved the lag/GPU issue but not the extension host crash
- Forum posts mention fixes work for macOS 26.0.0 and 26.0.1, but may not cover 26.1
- Standard Cursor 2.0.69 (stable) also fails identically on macOS 26.1
- VSCode (which uses similar Electron architecture) works fine on macOS 26.1
Logs Available
Full logs available at:
~/Library/Application Support/Cursor/logs/[timestamp]/main.log~/Library/Application Support/Cursor/logs/[timestamp]/exthost/exthost.log
Can provide full log files if needed.
Request
Is there active work to support macOS 26.1 specifically for extension host stability? The current nightly build has the Electron fixes but extension host crashes persist.
Workarounds That Don’t Help
- Downgrading to stable release
- Disabling extensions
- Running without GPU compositing
- Clearing all caches and settings
The only workaround that works is downgrading macOS, which is not practical for production systems.
System Info Summary:
- macOS: 26.1 (25B78)
- Cursor: 2.1.0-pre.18.patch.0
- Electron: 37.7.0
- Issue: Extension host crash code 5
- Status: Completely unusable
Steps to Reproduce
run cursor on 26.1
attempt to use
stuck on “planning next steps” (agent crashed)
Operating System
MacOS
Current Cursor Version (Menu → About Cursor → Copy)
2.1.0-pre.18.patch.0 (Nightly)
Does this stop you from using Cursor
Yes - Cursor is unusable
