[BUG] Claude Code extension crashes with "exit code 3" on Windows ARM64 (ProcessTransport not ready for writing)

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?

Description
The Claude Code VSCode extension consistently crashes approximately 15 seconds into any conversation on Windows ARM64 (Surface device). The extension starts normally and can briefly read/write files, but then terminates with "exit code 3" during normal message exchange. This happens on every conversation, including fresh ones.

The same extension version (2.1.49) works without issues on a Windows x64 machine, suggesting this is specific to the ARM64 build.

Steps to Reproduce
Install anthropic.claude-code-2.1.49-win32-arm64 on a Windows ARM64 device (Microsoft Surface)
Open a project in VSCode
Start a conversation with Claude Code
Send any message and wait ~15 seconds
The extension crashes with "exit code 3"
Expected Behavior
The extension should maintain a stable connection and complete the conversation without crashing.

Actual Behavior
The extension crashes approximately 15 seconds into every conversation. The underlying process terminates with exit code 3. The crash is reproducible on every attempt, including fresh conversations with no prior context.

Environment
Extension: anthropic.claude-code-2.1.49-win32-arm64
Device: Microsoft Surface (ARM64)
OS: Windows 11 Home (Build 10.0.26200)
VSCode: Latest version
Model: Claude Opus 4.6
Console Logs (from Developer Tools)

[Extension Host] rejected promise not handled within 1 second: Error: ProcessTransport is not ready for writing
[Extension Host] stack trace: Error: ProcessTransport is not ready for writing
at WW.write (extension.js:56:5839)
at _W.handleControlRequest (extension.js:57:161)

Uncaught (in promise) Error: cannot open _claude_vscode_fs_right:c%3A/Users/Bens/.claude/projects/.../memory/MEMORY.md
Detail: Unable to resolve filesystem provider with relative file path

ERR An unknown error occurred. Please consult the log for more details.
Troubleshooting Already Attempted
Reinstalled the extension
Reinstalled VSCode completely
Deleted the .claude folder
Tried fresh conversations with no context
None of these resolved the issue

What Should Happen?

The extension should maintain a stable connection and complete the conversation without crashing.

Error Messages/Logs

Console Logs (from Developer Tools)

[Extension Host] rejected promise not handled within 1 second: Error: ProcessTransport is not ready for writing
[Extension Host] stack trace: Error: ProcessTransport is not ready for writing
    at WW.write (extension.js:56:5839)
    at _W.handleControlRequest (extension.js:57:161)

Uncaught (in promise) Error: cannot open _claude_vscode_fs_right:c%3A/Users/Bens/.claude/projects/.../memory/MEMORY.md
Detail: Unable to resolve filesystem provider with relative file path

ERR An unknown error occurred. Please consult the log for more details.

Steps to Reproduce

Steps to Reproduce
Install anthropic.claude-code-2.1.49-win32-arm64 on a Windows ARM64 device (Microsoft Surface)
Open a project in VSCode
Start a conversation with Claude Code
Send any message and wait ~15 seconds
The extension crashes with "exit code 3"

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Extension latest version

Platform

Other

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_