Claude Code crashes on Windows ARM64 — Bun panic: incorrect alignment

Environment

• Claude Code: v2.1.49 (VS Code extension, win32-arm64)
• Bun: v1.3.10 (bundled, 1423d3c8)
• OS: Windows 11 ARM64 (Snapdragon)
• RAM: 68 GB

Description

Claude Code consistently crashes on Windows ARM64 with a Bun runtime panic: incorrect alignment. The crash happens during normal conversation flow (after stream starts, during or after response). It's reproducible — crashes every 1-2 minutes making the tool unusable.

Crash Log

Bun v1.3.10 (1423d3c8) Windows arm64
Windows v.win11_dt
CPU: neon fp aes crc32 atomics
Elapsed: 88458ms | User: 5750ms | Sys: 2703ms
RSS: 0.60GB | Peak: 0.70GB | Commit: 0.88GB | Faults: 586663 | Machine: 68.17GB

panic(thread 31996): incorrect alignment
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

Process exits with code 3 each time.

Bun Crash Report Links

• https://bun.report/1.3.10/W_11423d3cmgkgEuhogCwmzrfwl0uiBgyvBw32CwvhgmCw236lC4i16lCg6xjkBgsjufCYKERNEL32.DLLg0jCCSntdll.dlloqi1BA0eNrLzEvOLypKTS5RSMzJTM/LTc0rAQBMcwep

Steps to Reproduce

1. Install Claude Code VS Code extension on Windows 11 ARM64 (Snapdragon laptop)
2. Open any workspace
3. Start a conversation with Claude
4. Wait ~1-2 minutes — Bun crashes with panic: incorrect alignment
5. Extension shows: Error: Claude Code process exited with code 3

Expected Behavior

Claude Code should work reliably on ARM64 Windows without Bun runtime crashes.

Notes

• Bun's ARM64 Windows support is known to have alignment issues (see oven-sh/bun)
• Consider upgrading the bundled Bun version or providing a fallback runtime for ARM64
• Two crashes captured within 2 minutes in the VS Code output log, suggesting high frequency