Exit Code 3221225781 — Bun Runtime Crash on Windows 10

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?

System Information
Date Reported March 5, 2026
Operating System Windows 10
VS Code Extension Version anthropic.claude-code 2.1.69 (win32-x64)
Claude Code CLI Version 2.1.69 (npm-installed, works correctly)
Node.js Version v22.x.x LTS (freshly installed)
Affected Component VS Code Extension Panel (native-binary/claude.exe)

Bug Summary
The Claude Code VS Code extension fails to launch on Windows 10 with exit code 3221225781, which corresponds to Windows error 0xC0000005 (STATUS_ACCESS_VIOLATION). The bundled native binary (claude.exe) crashes immediately on startup due to a Bun runtime incompatibility with Windows 10.
The npm-installed CLI version works correctly and Claude Code functions normally when launched via the VS Code terminal using the 'claude' command.

What Should Happen?

The npm-installed CLI version works correctly and Claude Code functions normally when launched via the VS Code terminal using the 'claude' command.

Error Messages/Logs

Error Messages Observed
Primary Error
Error: Claude Code process exited with code 3221225781
Secondary Errors (from Output Logs)
⦁	Failed to load config cache: Error: Query closed before response received
⦁	Error processing client request: Error: Query closed before response received
⦁	Error spawning Claude: Error: Unsupported platform: win32-x64. No compatible Claude Code binary found
⦁	Error spawning Claude: Error: spawn UNKNOWN

Steps to Reproduce

Steps to Reproduce

1. Install Windows 10 (fully updated)
2. Install VS Code (latest version)
3. Install the Claude Code extension (anthropic.claude-code 2.1.69) from the VS Code Marketplace
4. Open VS Code and click the Claude Code panel icon
5. Observe the error: 'Claude Code process exited with code 3221225781'

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.69

Claude Code Version

2.1.69

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

Root Cause Analysis
The VS Code extension bundles a native claude.exe binary built with the Bun runtime. This Bun binary crashes immediately on Windows 10 with a STATUS_ACCESS_VIOLATION (0xC0000005) memory access error.
The issue was confirmed by running the bundled binary directly from PowerShell:
& "...\native-binary\claude.exe" --version → (silent crash, no output)
The npm-installed CLI running the same code via Node.js works perfectly:
node cli.js --version → 2.1.69 (Claude Code) ✓
Workarounds Attempted
⦁ Fresh reinstall of Claude Code npm package — did not fix (extension ignores npm binary)
⦁ Added claudeBinaryPath setting in VS Code settings.json pointing to npm claude.cmd and claude.ps1 — extension ignored the setting entirely
⦁ Replaced bundled claude.exe with cmd.exe copy — resulted in 'spawn UNKNOWN' error
⦁ Attempted to build replacement exe using pkg and nexe — cli.js uses import.meta (ES modules) which pkg does not support; nexe pre-built binaries unavailable for Node 18/20
⦁ Added Windows Defender exclusions for .claude and npm folders — no effect

Expected vs Actual Behavior
Expected
The Claude Code panel opens inside VS Code and the user can interact with Claude directly in the editor sidebar.
Actual
The panel immediately shows 'Error: Claude Code process exited with code 3221225781' and is non-functional. The bundled Bun binary crashes silently on startup.
Suggested Fix
Anthropic should investigate one or more of the following:
⦁ Update the bundled Bun runtime to a version that does not crash on Windows 10
⦁ Ensure the claudeBinaryPath VS Code setting is respected so users can point the extension to a working binary
⦁ Provide a Node.js-based fallback binary for Windows platforms where the Bun runtime is incompatible
⦁ Add a clear error message identifying the Bun crash specifically, rather than a generic exit code

Current Workaround
Claude Code can be used via the integrated terminal in VS Code by running the 'claude' command. This uses the npm-installed Node.js-based CLI and works correctly. However, this lacks the VS Code panel integration (inline diffs, sidebar chat, etc.) that the extension provides.