[BUG] Claude Code crashes with 0xC0000005 on Windows 11 when using Bun-based versions (v2.1.112+)

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?

Claude Code consistently crashes on Windows 11 with exit code 3221225477
(0xC0000005, Windows STATUS_ACCESS_VIOLATION).

The crash occurs both when using the Code tab in the Claude Desktop app and
when running affected standalone Claude Code CLI versions from a terminal.

On the same machine, the npm-installed Claude Code CLI v2.1.111 works
reliably. However, v2.1.112 and later consistently crash. This version
boundary appears to correlate with the transition from the Node.js-based CLI
to the Bun-based native Windows executable.

In Claude Desktop, the crash occurs after opening the Code tab, selecting a
working folder, and sending a message. The bundled Claude Code process then
terminates unexpectedly.

Relevant log output:

[warn] [HostLoop] cli.js stderr: Permission deny rule "JavaScript" matches no known tool — check for typos.

[error] Sentry caught: { eventId: '...', type: 'Error', value: 'write EOF', stack: 'Error: write EOF\n    at WriteWrap.onWriteComplete [as oncomplete] (node:internal/stream_base_commons:87:19)' }

[error] Session <id> query error: Claude Code process exited with code 3221225477

### What Should Happen?

Claude Code should start and operate normally on Windows 11 without crashing or terminating with exit code `3221225477` (`0xC0000005`), both in the Claude Desktop Code tab and when launched as a standalone CLI.

### Error Messages/Logs

```shell
Claude Code process exited with code 3221225477
(0xC0000005 = Windows STATUS_ACCESS_VIOLATION)

Relevant excerpt from Claude Desktop main.log:

[warn] [HostLoop] cli.js stderr: Permission deny rule "JavaScript" matches no known tool — check for typos.

[error] Sentry caught: { eventId: '<redacted>', type: 'Error', value: 'write EOF', stack: 'Error: write EOF\n    at WriteWrap.onWriteComplete [as oncomplete] (node:internal/stream_base_commons:87:19)' }

[error] Session <redacted> query error: Claude Code process exited with code 3221225477

Steps to Reproduce

Reproduction steps in Claude Desktop

1. Launch Claude Desktop on Windows 11.
2. Open the Code tab.
3. Select any working folder.
4. Send any message.
5. The Claude Code process crashes with the following error:

Claude Code process exited with code 3221225477

The exit code 3221225477 corresponds to 0xC0000005 (STATUS_ACCESS_VIOLATION on Windows).

Reproduction steps with the standalone CLI

1. Install one of the tested Claude Code CLI versions from v2.1.112 onward.
2. Open PowerShell or Command Prompt.
3. Run the following command:

claude

1. Start a session and send a message.
2. The Claude Code process crashes with exit code 3221225477 (0xC0000005).

Comparison with the last working version

On the same machine and in the same environment, Claude Code CLI v2.1.111 works reliably when pinned through npm:

npm install -g @anthropic-ai/claude-code@2.1.111

Test results:

• v2.1.111: Works normally and remains stable.
• Tested versions from v2.1.112 onward: The crash is reproducible.
• Claude Desktop Code: The crash is reproducible after selecting a folder and sending a message.

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.111

Claude Code Version

2.1.197 (bundled with Claude Desktop)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

System information

• OS: Windows 11 Pro, build 10.0.26100
• CPU: Intel Core Ultra 7 165H (Meteor Lake hybrid architecture with P-cores, E-cores, and LP E-cores)
• Claude Desktop package: Claude_1.18286.2.0_x64__pzs8sxrjxfjjc
• Bundled Claude Code version observed in the logs: v2.1.197
• Last known working standalone CLI version: v2.1.111
• Terminal: Windows Terminal / PowerShell
• API platform: Anthropic API

Version boundary

The issue is consistently reproducible with the tested CLI versions from v2.1.112 onward. The npm-installed v2.1.111 CLI works reliably on the same machine.

The observed version boundary appears to correlate with the transition from the Node.js-based CLI to the Bun-based native Windows executable. This is only a working hypothesis; I do not currently have a native crash dump or stack trace confirming the root cause.

Claude Desktop Code has also reproduced the crash in every desktop version I tested, including:

• Claude Desktop v1.3109.0
• Claude Desktop v1.1617.0
• The currently installed Microsoft Store version

With Claude Desktop v1.1617.0, Code proceeded as far as folder selection once, but then failed with the same error. After restarting the application, the reported process exit code changed to 1.

Troubleshooting already performed

• Tested multiple Claude Desktop versions; the crash remained reproducible.
• Switched between Sonnet and Opus; both reproduced the crash.
• Tested different working folders; the issue was not limited to a specific project.
• Pinned the npm-installed standalone CLI to v2.1.111; this version works reliably.
• Tested CLI versions from v2.1.112 onward; the crash was reproducible.
• Searched existing issues for 3221225477, 0xC0000005, STATUS_ACCESS_VIOLATION, and related Windows/Bun crash reports, but did not find an issue matching this specific crash and version boundary.

Because v2.1.111 works on the same machine while the tested versions from v2.1.112 onward crash, the issue does not appear to be caused by the selected model, working folder, or account.

The CPU uses Intel's Meteor Lake hybrid architecture. It may be useful to investigate native initialization, CPU feature detection, or another compatibility issue in the Windows executable or one of its native dependencies.