v2.1.15 crashes on CPUs without AVX (regression from 2.1.14)

[McSchnizzle]

Description

Claude Code v2.1.15 crashes immediately on startup with an "Illegal instruction" error on systems where the CPU lacks AVX support. This is a regression - v2.1.14 and earlier worked fine on the same system.

Environment

• OS: Ubuntu 24.04 (Linux Kernel v6.8.0, glibc v2.39)
• CPU: Intel Xeon Gold 6142 @ 2.60GHz (running in a VM without AVX passthrough)
• Claude Code version: 2.1.15 (crashes), 2.1.14 (works)
• Bun version (from crash output): Bun v1.3.6

Error Output

$ claude
============================================================
Bun v1.3.6 (d530ed99) Linux x64 (baseline)
Linux Kernel v6.8.0 | glibc v2.39
CPU: sse42 popcnt
Args: "claude"
Features: Bun.stderr(2) Bun.stdin(2) Bun.stdout(2) fetch(15) jsc no_avx2 no_avx spawn(4) standalone_executable 
Builtins: "bun:main" "node:assert" "node:async_hooks" ...

CPU lacks AVX support. Please consider upgrading to a newer CPU.
panic(main thread): Illegal instruction at address 0x4001FB4
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

Illegal instruction (core dumped)

Workaround

Rolling back to v2.1.14 resolves the issue:

ln -sf ~/.local/share/claude/versions/2.1.14 ~/.local/bin/claude

Notes

• The physical CPU (Xeon Gold 6142) supports AVX, but the VM hypervisor does not expose AVX instructions to the guest
• This is a common configuration in enterprise/cloud VM environments
• v2.1.14 binary is ~220MB, v2.1.15 is ~218MB - suggests a change in the Bun build used
• The crash output shows Features: ... no_avx2 no_avx ... indicating Bun detects the missing instructions but crashes anyway

Expected Behavior

Claude Code should work on systems without AVX support, as it did in v2.1.14 and earlier versions.

[github-actions]

Found 1 possible duplicate issue:

1. [BUG] Bun crashes with "CPU lacks AVX support. Please consider upgrading to a newer CPU." #19904

This issue will be automatically closed as a duplicate in 3 days.

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🤖 Generated with Claude Code

[rfmsanz-ethan]

+1

This is happening for me on Windows with ARM64 processor, and Mac M4 (ARM64) as well.

Reverted to 2.1.14 and everything is fine.

2.1.15 will not launch at all. This should be considered a major issue as ARM processors are becoming more and more common.

[rfmsanz-ethan]

Bun v1.3.6 (d530ed99) Windows x64 (baseline)
Windows v.win11_dt
CPU: sse42
Args: "C:\Users\***\.local\bin\claude.exe"
Features: Bun.stderr Bun.stdin(2) Bun.stdout(3) WebSocket fetch(53) jsc no_avx2 no_avx spawn(33) standalone_executable process_dlopen
Builtins: "bun:main" "node:assert" "node:async_hooks" "node:buffer" "node:child_process" "node:constants" "node:crypto" "node:domain" "node:events" "node:fs" "node:fs/promises" "node:http" "node:https" "node:module" "node:net" "node:os" "node:path" "node:path/posix" "node:path/win32" "node:perf_hooks" "node:process" "node:querystring" "node:stream" "node:timers/promises" "node:tls" "node:tty" "node:url" "node:util" "node:zlib" "node:worker_threads" "undici" "ws" "node-fetch" "node:inspector" "node:http2" "node:diagnostics_channel"
Elapsed: 6770ms | User: 2781ms | Sys: 4187ms
RSS: 0.84GB | Peak: 0.89GB | Commit: 0.90GB | Faults: 255656 | Machine: 17.17GB

CPU lacks AVX support. Please consider upgrading to a newer CPU.
panic(main thread): Illegal instruction at address 0x7FF7C4D680FC
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

This is a ARM64 (not x64) CPU via VM hypervisor.

[ericlevy]

Also affected on macOS.

OS: macOS (darwin-x64)
CPU: Pre-AVX Mac
Node: v20.19.0
Working version: 2.1.14 (from ~/.local/share/claude/versions/)

Same error: warn: CPU lacks AVX support followed by error: Invalid DNS result order.
Workaround confirmed: symlinking the cached 2.1.14 binary works.

[chushao]

Same issue and error message as ericlevy on macOS.
CPU is a M1 Pro.

Using 2.1.14 binary works.

[bwads001]

1. ✅ Added DISABLE_AUTOUPDATER=1 to ~/.claude/settings.json
2. ✅ Rolled back to Claude CLI 2.1.14
3. ✅ Verified 2.1.14 works without AVX crash

[MELTzx]

Also affected on Linux.

Architecture: x86_64
CPU(s): 4
On-line CPU(s) list: 0-3
Model name: Intel(R) Celeron(R) J4125 CPU @ 2.00GHz
Thread(s) per core: 1
Core(s) per socket: 4
Socket(s): 1
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon rep_good nopl cpuid tsc_known_freq pni pclmulqdq ssse3 cx16 sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave rdrand hypervisor lahf_lm 3dnowprefetch pti ssbd ibrs ibpb stibp fsgsbase tsc_adjust smep erms mpx rdseed smap clflushopt xsaveopt xsavec xgetbv1 md_clear arch_capabilities
Hypervisor vendor: Microsoft
Virtualization type: full
NUMA node0 CPU(s): 0-3

============================================================
Bun v1.3.6 (d530ed99) Linux x64 (baseline)
Linux Kernel v6.8.0 | glibc v2.39
CPU: sse42 popcnt
Args: "claude"
Features: Bun.stderr(2) Bun.stdin(2) Bun.stdout(2) fetch(21) jsc no_avx2 no_avx spawn(15) standalone_executable
Builtins: "bun:main" "node:assert" "node:async_hooks" "node:buffer" "node:child_process" "node:constants" "node:crypto" "node:domain" "node:events" "node:fs" "node:fs/promises" "node:http" "node:https" "node:module" "node:net" "node:os" "node:path" "node:path/posix" "node:path/win32" "node:perf_hooks" "node:process" "node:querystring" "node:stream" "node:timers/promises" "node:tls" "node:tty" "node:url" "node:util" "node:zlib" "node:worker_threads" "undici" "ws" "node-fetch" "node:inspector" "node:http2" "node:diagnostics_channel"
Elapsed: 8523ms | User: 3943ms | Sys: 1315ms
RSS: 1.20GB | Peak: 0.43GB | Commit: 1.20GB | Faults: 0 | Machine: 8.33GB

CPU lacks AVX support. Please consider upgrading to a newer CPU.
panic(main thread): Illegal instruction at address 0x4001FB4
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

[kamihork]

I encountered a similar problem on macOS, and it was resolved by rolling back to v2.1.14.

macOS Tahoe version26.0.1
Apple M2

$claude --version
warn: CPU lacks AVX support, strange crashes may occur. Reinstall Bun or use *-baseline build:
  https://github.com/oven-sh/bun/releases/download/bun-v1.3.6/bun-darwin-x64-baseline.zip
error: Invalid DNS result order.