[BUG] Cowork / Claude Code process exits with code 3221225501 on Windows 10 Pro 22H2

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude Code native binary crashes immediately on startup with exit code 3221225501
(0xC000001D - Illegal Instruction) when used through the Cowork desktop app on Windows 10.

The Cowork app shows: "Claude Code process exited with code 3221225501"

Tested binaries that crash:

• v2.1.128 (bundled with Cowork, at AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\claude-code\2.1.128\claude.exe)
• v2.1.138 (VS Code extension native binary)

Workaround found: npm install -g @anthropic-ai/claude-code@2.1.111 works in terminal
because it uses Node.js instead of the native Bun binary. However Cowork cannot use
this workaround as it relies on its own bundled binary.

What Should Happen?

Cowork should launch Claude Code and execute tasks successfully.

Error Messages/Logs

The Cowork app shows: "Claude Code process exited with code 3221225501"

Steps to Reproduce

1. Install Cowork desktop app on Windows 10 Pro 22H2
2. Open Cowork and navigate to the Cowork tab
3. Try to start a task
4. Claude Code process crashes immediately with exit code 3221225501

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.128 (Cowork bundled binary) / 2.1.111 (npm, works in terminal)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

The native Bun-based binary (v2.1.112+) crashes with exit code 3221225501 (0xC000001D -
Illegal Instruction) on Windows 10 Pro 22H2.

v2.1.111 installed via npm works correctly in terminal because it uses Node.js instead
of the native Bun binary. However Cowork uses its own bundled binary and cannot use
this workaround.

Replacing the Cowork bundled claude.exe with the v2.1.111 binary still crashes,
suggesting a deeper incompatibility with Windows 10 in recent Bun builds.

This issue also affects the VS Code extension (v2.1.138).