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[Bug] Sidecar crashes with exit code 3221226505 (0xC0000409) on Windows - causes local server to go offline #28413
Description
Description
Environment
- OS: Windows 10 (10.0.19045)
- OpenCode Desktop: v1.15.5
- Plugin: oh-my-openagent@4.0.0
What happens
The sidecar backend process randomly crashes with exit code 3221226505 (0xC0000409 = STATUS_STACK_BUFFER_OVERRUN), causing the local server to go offline. UI shows "prompt send failure". The crash happens both during active use and while idle. Only fix is restarting OpenCode.
Log evidence (main.log)
[2026-05-14 16:15:43] sidecar exited { code: 3221226505 } [2026-05-18 08:09:54] sidecar exited { code: 3221226505 } [2026-05-19 08:06:20] sidecar exited { code: 3221226505 } [2026-05-19 16:01:59] sidecar exited { code: 3221226505 } [2026-05-19 16:26:18] sidecar exited { code: 3221226505 } [2026-05-20 08:57:03] sidecar exited { code: 3221226505 }
Error code
0xC0000409 = STATUS_STACK_BUFFER_OVERRUN
Windows security exception triggered by stack buffer overrun detection in the sidecar process.
Notes
- Reproducible across v1.14.x → v1.15.5 (not a regression, persistent issue)
- Crash occurs both during active conversation and while idle
- Works fine when using OpenCode via VS Code extension (CLI mode) on the same machine
Plugins
No response
OpenCode version
No response
Steps to reproduce
No response
Screenshot and/or share link
No response
Operating System
No response
Terminal
No response
Activity
github-actions commentedon May 20, 2026
This issue doesn't fully meet our contributing guidelines.
What needs to be fixed:
_No response_). Please provide the exact version._No response_). Even if the crash is random/intermittent, please describe the conditions under which it occurs.Please edit this issue to address the above within 2 hours, or it will be automatically closed.
This issue might be a duplicate of existing issues. Please check:
oh-my-opencodeplugin loaded (Desktop app, same plugin/OS combination)If you believe this was flagged incorrectly, please let a maintainer know.
github-actions commentedon May 20, 2026
This issue has been automatically closed because it was not updated to meet our contributing guidelines within the 2-hour window.
Feel free to open a new issue that follows our issue templates.