[BUG] Missing HCS services: vfpext — persists on Windows 11 Pro ARM64 (Surface Pro 11th Edition/Snapdragon) after full Hyper-V repair

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?

Attempting to enable Cowork in Claude Desktop fails with the error "Missing HCS services: vfpext". Hyper-V is fully enabled (all sub-features report "Enabled"), and extensive repair attempts have not resolved it. Diagnosis shows the vfpext.sys driver's payload exists correctly in the Windows component store (WinSxS) for this system's architecture, but the deployment step that would place it in System32\drivers and register its service never executes — no DISM repair, SFC scan, or feature re-enable triggers it.

What Should Happen?

Cowork should be able to detect and use Hyper-V's HCS services given that Hyper-V and all its sub-features are confirmed "Enabled" at the OS level, or at minimum provide guidance beyond a generic missing-service error when this specific deployment gap occurs.

Error Messages/Logs

Cowork UI error: "Missing HCS services: vfpext"

PowerShell verification:
> sc.exe query vfpext
[SC] EnumQueryServicesStatus:OpenService FAILED 1060:
The specified service does not exist as an installed service.

> Test-Path C:\Windows\System32\drivers\vfpext.sys
False

(vfpext.sys is confirmed present and architecture-correct under C:\Windows\WinSxS\, and the parent Microsoft-Hyper-V-Services feature reports "Enabled".)

Steps to Reproduce

1. On a Windows 11 Pro ARM64 (Qualcomm Snapdragon) device, with Hyper-V and all sub-features enabled via Enable-WindowsOptionalFeature
2. Open Claude Desktop and attempt to enable the Cowork tab
3. Observe error: "Missing HCS services: vfpext"
4. Confirm via PowerShell that the vfpext service/driver is absent despite Hyper-V reporting fully enabled (see Error Messages/Logs)

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude 1.22209.0 (77c938) 2026-07-16T05:39:45.000Z

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

_No response_