Claude Code v2.0.27 fails with SIGILL on Intel Mac without AVX2 support

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 v2.0.27 crashes with Error: Claude Code process terminated by signal SIGILL on older Intel Macs that don't support AVX2 CPU instructions.

What Should Happen?

The SIGILL error indicates that Claude Code was compiled with AVX2 requirements, but this CPU doesn't support those instructions. The application crashes both in the Terminal and in VS Code.

Error Messages/Logs

Error: Claude Code process terminated by signal SIGILL

Steps to Reproduce

Install Claude Code on an Intel Mac without AVX2 support
Run claude in Terminal or use in VS Code
Try to execute any command

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.0.27 claude code

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

System Information:

OS: macOS
CPU: Intel x86_64
CPU Features: FPU VME DE PSE TSC MSR PAE MCE CX8 APIC SEP MTRR PGE MCA CMOV PAT PSE36 CLFSH DS ACPI MMX FXSR SSE SSE2 SS HTT TM PBE SSE3 PCLMULQDQ DTES64 MON DSCPL VMX SMX EST TM2 SSSE3 CX16 TPR PDCM SSE4.1 SSE4.2 POPCNT AES PCID
Missing: AVX2, BMI2, FMA
Node.js: v20.11.0
Claude Code: v2.0.27