›_ Claude Code Issues
Claude Code Issues / #19666

[BUG] Claude Code crashes with Bun panic in Visual Studio Code on Windows 11

Open 💬 19 comments Opened Jan 21, 2026 by DenisKrav

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?

Environment
OS: Windows 11
VS Code Extension: Claude Code v2.1.11
Bundled Bun version: v1.3.5 (1e86cebd)
CPU: x64 (baseline) with sse42, avx, avx2

Problem
Claude's code constantly crashes when opening a certain project, but even on projects that work, the error appears. The extension works fine on other projects. The crash occurs during initialization with a Bun panic error.

Observations

  1. The --model "d" argument appears truncated/corrupted (should be full model name or "default")
  2. Memory usage is very high (3.54GB RSS) before crash
  3. Crash happens consistently on this project but not on others
  4. Crash report URL: https://bun.report/1.3.5/e_11e86cebGugogCw+kiM65ioJgqpmMCYKERNEL32.DLLut0LCSntdll.dll4zijBA0eNoFwcENACAMAsBVWM1ENHyosXzc3js53LyYxYYrWApkTHbkEZWRd/gBNAAPKQ

What I tried (none of these helped)

  1. Installed global Bun v1.3.6 (extension still uses bundled v1.3.5)
  2. Deleted .claude folder in project directory
  3. Deleted tmpclaude-* temporary folders
  4. Reinstalled the extension
  5. Restarted VS Code

What Should Happen?

Expected behavior
Claude Code should start normally without crashing.

Additional context
The project is a medium-sized backend application with multiple subfolders. Other projects open without issues on the same machine with the same extension version.

Error Messages/Logs

Args: "c:\Users\ACER\.vscode\extensions\anthropic.claude-code-2.1.11-win32-x64\resources\native-binary\claude.exe" "--output-format" "stream-json" "--verbose" "--input-format" "stream-json" "--max-thinking-tokens" "0" "--model" "d"...

Elapsed: 4531ms | User: 2250ms | Sys: 2265ms
RSS: 3.54GB | Peak: 3.54GB | Commit: 3.56GB | Faults: 873251 | Machine: 34.19GB

panic(thread 18532): integer does not fit in destination type
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

Steps to Reproduce

  1. Install Claude Code extension v2.1.11 on VS Code (Windows 11)
  2. Open a project with multiple subfolders and files (in my case: c:\Project_programing\Work\Yieldy\nytroseo\back)
  3. Open Claude Code panel in VS Code
  4. Extension attempts to initialize and index the project
  5. Bun crashes with panic error before Claude Code becomes usable

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.11

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_

View original on GitHub ↗

19 Comments

github-actions[bot] · 5 months ago

Found 3 possible duplicate issues:

  1. https://github.com/anthropics/claude-code/issues/19439
  2. https://github.com/anthropics/claude-code/issues/19453
  3. https://github.com/anthropics/claude-code/issues/18567

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

  • If your issue is a duplicate, please close it and 👍 the existing issue instead
  • To prevent auto-closure, add a comment or 👎 this comment

🤖 Generated with Claude Code

Zamaroht · 5 months ago

I started getting this too, I can't use claude code

panic(thread 1441708): integer does not fit in destination type
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

IsmailHassani · 4 months ago

Same here. Every command will trigger this issue.
This is the crash report: https://bun.report/1.3.10/W_11423d3cmgkgEuhogCwmzrfg36uiBw4sC4k8gmCg916lCg6xjkBgsjufCYKERNEL32.DLLg0jCCSntdll.dlloqi1BA0eNrLzEvOLypKTS5RSMzJTM/LTc0rAQBMcwep

XekriRedmane · 4 months ago

Same with 2.1.47.

Bun v1.3.10 (1423d3c8) Windows arm64
Windows v.win11_dt
CPU: neon fp aes crc32 atomics
Args: "C:\Users\rober\.local\bin\claude.exe"
Features: Bun.stderr(2) Bun.stdin(2) Bun.stdout(2) abort_signal(2) fetch(17) jsc spawn(11) standalone_executable process_dlopen(2) yaml_parse(5)
Builtins: "bun:main" "node:assert" "node:async_hooks" "node:buffer" "node:child_process" "node:constants" "node:crypto" "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:stream" "node:timers/promises" "node:tls" "node:tty" "node:url" "node:util" "node:zlib" "node:worker_threads" "undici" "ws" "node:http2"
Elapsed: 60900ms | User: 5921ms | Sys: 1515ms
RSS: 0.61GB | Peak: 0.66GB | Commit: 0.79GB | Faults: 234909 | Machine: 33.90GB

panic(thread 29508): incorrect alignment
oh no: Bun has crashed. This indicates a bug in Bun, not your code.
XekriRedmane · 4 months ago

2.1.45 does not seem to have this issue.

XekriRedmane · 4 months ago

2.1.49 still has the issue.

DenisKrav · 4 months ago
2.1.49 still has the issue.

I use 2.1.47. But doesn`t try newest version

XekriRedmane · 4 months ago

Further note: I am using claude CLI, and just starting claude and waiting about a minute will cause a crash. You don't have to do anything, just run claude and wait.

AaronHallAttorney · 4 months ago

Experiencing the same class of crash on Windows 11 ARM64.

Environment:

  • OS: Windows 11 Home ARM64 (10.0.26200)
  • Bun: v1.3.10 (1423d3c8) Windows arm64
  • Binary: C:\Users\aaron\.local\bin\claude.exe

Crash output:
panic(thread 20224): incorrect alignment
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

Elapsed: 82510ms | User: 1890ms | Sys: 812ms
RSS: 0.54GB | Peak: 0.58GB | Commit: 0.76GB | Faults: 163483 | Machine: 33.90GB

Also noting: the crash report link shown in the terminal is broken/non-functional.

Kulitorum · 4 months ago

Same crash - happens quite a lot.

RoboLagoon · 4 months ago

I also see random Bun crashes, Claude Code has 5k+ issues, this is getting crazy

4riel · 4 months ago

Same crash, happens every single time directly in CC. Version 2.1.50

AaronHallAttorney · 4 months ago

For 5 days, Bun has been crashing every time. It was totally unusable. I went back to the Node.js version (npm) and all is good again.

GarryMcCord · 4 months ago

Crashes even if you don't use Bun.

Semant1ka · 4 months ago

Same scenario as @XekriRedmane described:

  • Claude Code CLI v2.1.51
  • Crashes with Bun out of memory error regularly, regardless of activity
  • OS: Windows 10 Home Edition

The problem resolved after system restart. Looks like a memory leak 🤷

somoreingold · 3 months ago

Is anyone using software like Windhawk (https://windhawk.net/)? I noticed the bun crash happens when it's active.

WaterTian · 3 months ago

Same crash here on Windows 11. Found that statusline plugins make it way worse — they fire on every tick, so Bun's allocator gets hammered constantly.

Switched to npm i -g @anthropic-ai/claude-code + cc-hud (lightweight Node.js statusline). No crashes since.

zrajnai-shapr3d · 2 months ago
Is anyone using software like Windhawk (https://windhawk.net/)? I noticed the bun crash happens when it's active.

This was the cause for me.

https://github.com/ramensoftware/windhawk/issues/836

Adding claude.exe to Windhawk's exclusion list (under settings / advanced settings / more advanced settings) is a workaround to fix this.

soroushm · 1 month ago

same for me, its the report from claude cli runing in terminal on webstorm

un v1.3.14 ([2a41ca9](<https://github.com/oven-sh/bun/tree/2a41ca974b7302952252a20eddbb3b5c3f2dee9b>)) on windows x86_64_baseline [StandaloneExecutable]

panic: integer overflow

  • [Allocator.zig:443](<https://github.com/oven-sh/zig/blob/bun-2a41ca974b7302952252a20eddbb3b5c3f2dee9b/lib/std/mem/Allocator.zig#L443>): free
  • [array_list.zig:655](<https://github.com/oven-sh/zig/blob/bun-2a41ca974b7302952252a20eddbb3b5c3f2dee9b/lib/std/array_list.zig#L655>): deinit
  • [HTTPContext.zig:220](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/HTTPContext.zig#L220>): deinit
  • [ref_count.zig:148](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/ptr/ref_count.zig#L148>): derefWithContext
  • [ref_count.zig:118](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/ptr/ref_count.zig#L118>): deref
  • [http.zig:755](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/http.zig#L755>): deinit
  • [AsyncHTTP.zig:400](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/AsyncHTTP.zig#L400>): onAsyncHTTPCallback
  • [http.zig:2538](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/http.zig#L2538>): wrapped_callback
  • [http.zig:2524](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/http.zig#L2524>): run
  • [http.zig:2212](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/http.zig#L2212>): fail
  • [http.zig:438](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/http.zig#L438>): onClose
  • [HTTPContext.zig:462](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/HTTPContext.zig#L462>): onClose
  • [uws_handlers.zig:229](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/runtime/socket/uws_handlers.zig#L229>): fwd
  • [uws_handlers.zig:241](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/runtime/socket/uws_handlers.zig#L241>): onClose
  • [vtable.zig:61](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/uws_sys/vtable.zig#L61>): call
  • [vtable.zig:84](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/uws_sys/vtable.zig#L84>): on_close
  • [openssl.c:952](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/packages/bun-usockets/src/crypto/openssl.c#L952>): us_internal_ssl_on_close
  • [socket.c:306](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/packages/bun-usockets/src/socket.c#L306>): us_internal_socket_close_raw
  • [context.c:125](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/packages/bun-usockets/src/context.c#L125>): us_socket_group_close_all_ex
  • [SocketGroup.zig:74](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/uws_sys/SocketGroup.zig#L74>): closeAll
  • [HTTPContext.zig:224](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/HTTPContext.zig#L224>): deinit
  • [ref_count.zig:148](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/ptr/ref_count.zig#L148>): derefWithContext
  • [ref_count.zig:118](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/ptr/ref_count.zig#L118>): deref
  • [http.zig:755](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/http.zig#L755>): deinit
  • [AsyncHTTP.zig:400](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/AsyncHTTP.zig#L400>): onAsyncHTTPCallback
  • [http.zig:2538](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/http.zig#L2538>): wrapped_callback
  • [http.zig:2524](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/http.zig#L2524>): run
  • [http.zig:2212](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/http.zig#L2212>): fail
  • [http.zig:450](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/http.zig#L450>): onTimeout
  • [HTTPContext.zig:558](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/HTTPContext.zig#L558>): onLongTimeout
  • [uws_handlers.zig:229](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/runtime/socket/uws_handlers.zig#L229>): fwd
  • [uws_handlers.zig:247](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/runtime/socket/uws_handlers.zig#L247>): onLongTimeout
  • [vtable.zig:61](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/uws_sys/vtable.zig#L61>): call
  • [vtable.zig:92](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/uws_sys/vtable.zig#L92>): on_long_timeout
  • [loop.c:212](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/packages/bun-usockets/src/loop.c#L212>): us_internal_timer_sweep
  • [timer.c:192](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/vendor/libuv/src/timer.c#L192>): uv__run_timers
  • [core.c:750](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/vendor/libuv/src/win/core.c#L750>): uv_run
  • [Loop.zig:273](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/uws_sys/Loop.zig#L273>): run
  • [HTTPThread.zig:643](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/HTTPThread.zig#L643>): processEvents
  • [HTTPThread.zig:253](<https://github.com/oven-sh/bun/blob/2a41ca974b7302952252a20eddbb3b5c3f2dee9b/src/http/HTTPThread.zig#L253>): onStart
  • [Thread.zig:509](<https://github.com/oven-sh/zig/blob/bun-2a41ca974b7302952252a20eddbb3b5c3f2dee9b/lib/std/Thread.zig#L509>): callFn
  • [Thread.zig:622](<https://github.com/oven-sh/zig/blob/bun-2a41ca974b7302952252a20eddbb3b5c3f2dee9b/lib/std/Thread.zig#L622>): entryFn

Features: spawn, standalone\_executable, yaml\_parse, claude\_code, Bun.stderr, Bun.stdin, Bun.stdout, abort\_signal, fetch, http\_server, jsc