›_ Claude Code Issues
Claude Code Issues / #20674

[BUG] Both VS Code extension and CLI crash with Bun v1.3.5 "integer does not fit in destination type" on Windows 11 - v2.1.19 still affected

Resolved 💬 4 comments Opened Jan 24, 2026 by nodays-off Closed Mar 1, 2026

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?

Both the VS Code extension (v2.1.17) and CLI (v2.1.19) crash with the same Bun v1.3.5 panic error on Windows 11. The crash occurs consistently during startup or when browsing menus like /plugin.

Environment:

  • OS: Windows 11
  • RAM: 68GB total
  • Claude Code versions tested: v2.1.17 (VS Code), v2.1.19 (CLI)
  • Bundled Bun version: v1.3.5 (1e86cebd)

Error:

RSS: 3.56GB - 4.57GB before crash
panic(thread): integer does not fit in destination type
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

What I tried (none worked):

  • Removed all global MCP servers from .claude.json
  • Deleted project-specific .claude folders
  • Cleared .claude.json completely (extension reset to defaults)
  • Switched between projects
  • Used both Opus and Sonnet models
  • Reinstalled VS Code extension multiple times
  • Updated to latest CLI version (v2.1.19)

Additional context:

Expected behavior:
Claude Code should start normally without crashing. The bundled Bun version should be updated to v1.3.6 or later to fix the integer overflow bug.

What Should Happen?

Claude Code should start and run normally without crashing

Error Messages/Logs

============================================================
Bun v1.3.5 (1e86cebd) Windows x64 (baseline)
Windows v.win11_dt
CPU: sse42 avx avx2 avx512
Args: "c:\Users\olaid\.vscode\extensions\anthropic.claude-code-2.1.17-win32-x64\resources\native-binary\claude.exe" "--output-format" "stream-json" "--verbose" "--input-format" "stream-json" "--max-thinking-tokens" "31999" "--m"...
Features: Bun.stderr(2) Bun.stdin(2) Bun.stdout(2) fetch(14) jsc spawn(11) 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: 1491ms | User: 1578ms | Sys: 1031ms
RSS: 3.59GB | Peak: 3.59GB | Commit: 3.71GB | Faults: 882385 | Machine: 67.79GB

panic(thread 34128): integer does not fit in destination type
oh no: 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:

https://bun.report/1.3.5/e_11e86cebGugogCw+kiM65ioJgqpmMCYKERNEL32.DLLut0LCSntdll.dll4zijBA0eNoFwcENACAMAsBVWM1ENHyosXzc3js53LyYxYYrWApkTHbkEZWRd/gBNAAPKQ

Steps to Reproduce

  1. Install Claude Code v2.1.17 VS Code extension or v2.1.19 CLI on Windows 11
  2. Open VS Code in any project directory (or run claude in PowerShell)
  3. Start Claude Code (click Spark icon in VS Code, or run claude command)
  4. Wait 1-60 seconds
  5. Bun crashes with "integer does not fit in destination type" error

Alternative reproduction path:

  1. Start Claude Code CLI successfully
  2. Navigate to /plugin menu
  3. Browse plugins for ~50 seconds
  4. Same Bun crash occurs (RSS: 4.57GB)

Reproducibility:

  • 100% consistent across multiple attempts
  • Affects both VS Code extension and CLI
  • Happens on multiple different projects
  • Config cleanup (removing MCP servers, deleting .claude folders) doesn't fix it

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

Yes, this worked in a previous version (It was working perfectly before it suddenly stopped)

Claude Code Version

2.1.17 (VS Code), 2.1.19 (CLI) (Same versions - it worked initially, then degraded)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

Full crash logs available if needed. The issue affects multiple Windows 11 users based on existing GitHub issues #19439, #19666, and #18567.

Memory usage pattern: 3.5-4.6GB RSS before crash occurs.

Workaround: None currently available. Web interface (claude.ai) works as expected.

View original on GitHub ↗

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