[BUG] Cowork sandbox fails to connect on Windows ARM64 despite sucessful VM boot and file operations

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?

Cowork fails to start the sandbox execution environment on my ASUS Zenbook A14 (Snapdragon X Plus, ARM64).

The workspace partially works: Claude can create, read, edit, move, and organize files successfully. However, any task requiring terminal access or code execution fails because the sandbox never becomes available.

The issue occurs consistently and survives reboots, WSL reinstallation, Ubuntu installation, Hyper-V configuration, and Docker removal.

Based on the logs, the VM bundle downloads correctly, the VM boots successfully, and workspace files are accessible. The failure occurs when the guest environment attempts to establish its connection back to Claude.

What Should Happen?

Cowork should start successfully and provide terminal/sandbox access.

Claude should be able to execute commands, run Python scripts, install packages, and perform other sandbox-based actions in addition to normal file operations.

Error Messages/Logs

Primary error:

VM connection timeout after 60 seconds

Relevant log entries:

* Connection timeout, last completed step: add_plan9_shares
* VM connection timeout after 60 seconds
* connect ENOENT cowork-vm-service
* VM service not running. The service failed to start.

Additional observations:

* rootfs.vhdx downloads successfully
* vmlinuz downloads successfully
* initrd downloads successfully
* VM boot completes successfully
* File operations work normally
* Terminal/sandbox execution fails

Steps to Reproduce

1. Open Claude Desktop on Windows ARM64.
2. Start a Cowork session.
3. Wait for workspace initialization.
4. Ask Cowork to execute a Python script or run a terminal command.
5. Observe that the workspace times out and sandbox execution is unavailable.

Reproducibility: 100%

Claude Model

Sonnet (default)

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.162 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

Troubleshooting already performed:

• Upgraded from Windows 11 Home to Windows 11 Pro
• Enabled virtualization in BIOS
• Enabled Hyper-V
• Enabled Virtual Machine Platform
• Installed and updated WSL2
• Installed Ubuntu and completed initialization
• Removed Docker Desktop
• Rebooted multiple times
• Deleted and recreated Cowork VM bundles
• Verified VM-related services are running

Interesting behavior:

• File operations work correctly (create, read, edit, move files)
• Sandbox execution does not work
• Cowork can manipulate workspace contents but cannot execute code
• Vmmem and WorkloadsSessionHost processes appear during startup, indicating the VM is launching
• Issue appears specific to the sandbox/guest connection layer rather than VM creation itself