[BUG] Not able to start claude.exe because of a AVX support for Bun in versions 2.1.75 and higher

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?

When I try to launch 2.1.75 - 2.1.77 I get this when trying to start claude.exe:

C:\>claude
============================================================
←[0m←[2mBun v1.3.11 (a2743b6d) Windows x64 (baseline)
Windows v.win10_cu
Args:
Features: no_avx2 no_avx
Elapsed: 2ms | User: 0ms | Sys: 0ms
RSS: 16.21MB | Peak: 16.23MB | Commit: 56.41MB | Faults: 4541
←[0m
CPU lacks AVX support. Please consider upgrading to a newer CPU.
←[31mpanic←[0m←[2m(thread 676340): ←[0mattempt to use null value
oh no←[0m←[2m:←[0m Bun has crashed. This indicates a bug in Bun, not your code.

To send a redacted crash report to Bun's team,
please file a GitHub issue using the link below:

←[36m https://bun.report/1.3.11/e_1a2743b6AggggggDm2Lgujl4DCAgrmFCA282fA0
←[0m

As a work around I have been copying 2.1.74 over claude.exe as I was fortunate enough to still have it on my machine when this started, and disable auto-update:

copy C:\Users\<user>\.local\share\claude\versions\2.1.74 C:\Users\<user>\.local\bin\claude.exe


What Should Happen?

Claude should just start.

Error Messages/Logs

============================================================
←[0m←[2mBun v1.3.11 (a2743b6d) Windows x64 (baseline)
Windows v.win10_cu
Args:
Features: no_avx2 no_avx
Elapsed: 2ms | User: 0ms | Sys: 0ms
RSS: 16.21MB | Peak: 16.23MB | Commit: 56.41MB | Faults: 4541
←[0m
CPU lacks AVX support. Please consider upgrading to a newer CPU.
←[31mpanic←[0m←[2m(thread 676340): ←[0mattempt to use null value
oh no←[0m←[2m:←[0m Bun has crashed. This indicates a bug in Bun, not your code.

To send a redacted crash report to Bun's team,
please file a GitHub issue using the link below:

←[36m https://bun.report/1.3.11/e_1a2743b6AggggggDm2Lgujl4DCAgrmFCA282fA0
←[0m

Steps to Reproduce

Well be on a machine that may or may not have AVX CPU support and try to start Claude.exe.

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.74

Claude Code Version

2.1.75 and upwards

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_