[BUG] Cowork "Virtualization is not available" on Windows 11 Pro 25H2 — all virtualization features enabled, VM never initializes

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?

The Cowork tab permanently shows "Virtualization is not available — Claude's workspace requires Virtual Machine Platform, but the virtualization service isn't responding. Restart your computer to resolve this."

Restarting does not resolve it. The VM never initializes. No logs are generated under %APPDATA%\Claude\logs\. The CoworkVMService is running but Cowork never progresses past the error screen. Chat and Code tabs work fine — only Cowork is affected.

This issue has persisted since I first subscribed to Claude Pro. I have never been able to use Cowork.

NOTE: This is about Claude Cowork (Desktop app), not the Claude Code CLI. This appears to be the same tracker used for Cowork bugs.

What Should Happen?

Cowork should detect that all virtualization features are enabled and successfully start the VM workspace.

Error Messages/Logs

Error displayed: "Virtualization is not available — Claude's workspace requires Virtual Machine Platform, but the virtualization service isn't responding. Restart your computer to resolve this."

No log file exists at %APPDATA%\Claude\logs\cowork_vm_node.log — the VM never attempts to start.

Steps to Reproduce

1. Install Claude Desktop on Windows 11 Pro 25H2 (Build 26200.8246)
2. Ensure Hyper-V, Virtual Machine Platform, and Windows Hypervisor Platform are all enabled
3. Ensure bcdedit hypervisorlaunchtype is set to Auto
4. Launch Claude Desktop and navigate to the Cowork tab
5. Observe "Virtualization is not available" error immediately
6. Restart computer — error persists

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

Claude Desktop 1.3883.0 (direct installer from claude.ai/download)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Windows Terminal

Additional Information

System Specs

• ASUS ROG Zephyrus M16 GU603ZM
• 12th Gen Intel Core i7-12700H
• 40 GB DDR5 RAM
• NVIDIA RTX 3060 + Intel Iris Xe
• Windows 11 Pro 25H2, Build 26200.8246

Virtualization Verification (All Pass)

systeminfo: "A hypervisor has been detected"
bcdedit hypervisorlaunchtype: Auto
Hyper-V: Enabled
VirtualMachinePlatform: Enabled
HypervisorPlatform: Enabled
CoworkVMService: Running

Install Methods Tested (Both Fail)

1. Microsoft Store version (Claude_1.3883.0.0_x64 via WindowsApps) — same error
2. Direct installer from claude.ai/download, run as Administrator — same error after reboot

Key Finding

No logs directory exists at %APPDATA%\Claude\logs\ — the VM bundle never attempts to start despite CoworkVMService running.

Support Contact

Anthropic support contacted — human agent escalation pending (Conversation ID: 215473639830439). Support confirmed this is a known detection bug.

Related Issues

#27316, #27420, #29532, #29887, #32004, #37265, #40359, #45446, #45715, #49664, #50348

Anthropic issues.pdf