claude-code - 💡(How to fix) Fix [BUG] Segmentation fault at address 0x8 on startup - Windows 11 (Bun baseline build)

Preflight Checklist

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

What's Wrong?

Claude Code crashes immediately on startup with a segmentation fault at address 0x8. The process exits before any interactive session begins.

What Should Happen?

Claude Code should start normally and display the interactive CLI interface.

Error Messages/Logs

Bun v1.3.14 (521eedd6) Windows x64 (baseline)
Windows v.win11_dt
CPU: sse42 avx avx2
Args: "claude"
Features: Bun.stderr(2) Bun.stdin(2) Bun.stdout(2) fetch jsc spawn(2) standalone_executable yaml_parse claude_code
Elapsed: 351ms | User: 250ms | Sys: 203ms
RSS: 0.25GB | Peak: 0.25GB | Commit: 0.32GB | Faults: 61999 | Machine: 33.75GB
panic(main thread): Segmentation fault at address 0x8
panic: Segmentation fault at address 0x8
panicked during a panic. Aborting.

Steps to Reproduce

1. Install Claude Code: npm install -g @anthropic-ai/claude-code
2. Run: claude
3. Process crashes immediately with segfault before any UI is shown

Claude Model

None

Is this a regression?

I don't know

Last Working Version

No response

Claude Code Version

2.1.150 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

The Bun build variant is "baseline" (Windows x64 baseline), which targets maximum CPU compatibility (sse42 avx avx2, no AVX-512). It is unclear whether a non-baseline build would behave differently.

Reinstalling from scratch (npm uninstall -g + cache clean + reinstall) does not resolve the issue. The crash is 100% reproducible on every invocation.

Machine RAM: 33.75GB. The fault address 0x8 suggests a null pointer dereference (offset from a NULL pointer).