[BUG] Claude workspace sandbox always fails on Windows — VHDX files never created by installer, manual fix steps included

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?

On Windows 11, Claude Desktop's workspace fails to start because the installer never creates the required VHDX files (rootfs.vhdx, smol-bin.vhdx) or the .verified file. This affects multiple machines. Sandbox error. The error cycles through:

• "VHDX file not found: ...rootfs.vhdx"
• "VM service not running. The service failed to start."
• "smol-bin not found: ...smol-bin.vhdx"
• "SDK version not verified at /mnt/virtio..."

Reinstalling the workspace does not fix it. Affects two separate Lenovo ThinkPad Windows 11 machines.

What Should Happen?

The installer should automatically create all required VHDX files and the .verified file. Currently they are never created and the workspace is permanently broken until manually fixed.

Error Messages/Logs

failed to set VHDX path: VHDX file not found
VM service not running. The service failed to start.
failed to set smol-bin path: smol-bin not found
RPC error -1: SDK version not verified at /mnt/virtio-root/shared/.../.verified

Steps to Reproduce

1. Install Claude Desktop fresh on Windows 11
2. Open Claude and try to use the workspace
3. Workspace immediately fails with VHDX errors
4. Clicking "Reinstall the workspace" does not fix it
5. Error persists across restarts and full reinstalls

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

1.11847.5.0

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_