[BUG] Cowork fails with HYPERVISOR_SERVICE_ERROR on ASUS ROG Maximus XII Extreme / i7-10700K — bcdedit hypervisorlaunchtype auto freezes boot

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?

What's Wrong

Cowork fails with HYPERVISOR_SERVICE_ERROR. The hypervisor does not launch at boot despite all Hyper-V features being fully enabled. Setting bcdedit /set hypervisorlaunchtype auto causes Windows to freeze at boot and enter diagnostic/repair mode every time — even after updating BIOS to the latest version (3201). No third-party virtualization software (VMware, VirtualBox) is installed.

---

System Info
| Item | Value |
|---|---|
| OS | Windows 11 Pro, Build 26200 |
| Motherboard | ASUS ROG Maximus XII Extreme |
| CPU | Intel Core i7-10700K @ 3.80GHz |
| RAM | 32GB |
| BIOS | American Megatrends v3201 (updated 3/22/2026) |
| Secure Boot | Enabled |
| Claude Desktop | v1.1.7714.0 |
| Subscription | Pro |

---

Windows Features Enabled
| Feature | State |
|---|---|
| Microsoft-Hyper-V | Enabled |
| Microsoft-Hyper-V-Hypervisor | Enabled |
| Microsoft-Hyper-V-All | Enabled |
| Microsoft-Hyper-V-Services | Enabled |
| Microsoft-Hyper-V-Tools-All | Enabled |
| HypervisorPlatform | Enabled |
| VirtualMachinePlatform | Enabled |
| CoworkVMService | Running |
| vmms (Hyper-V Virtual Machine Management) | Running |
| vmcompute (Hyper-V Host Compute Service) | Running |

Hardware Virtualization
| Check | Result |
|---|---|
| VirtualizationFirmwareEnabled | True |
| VMMonitorModeExtensions | True |
| SecondLevelAddressTranslationExtensions | True |
| VT-d (Directed I/O) | Enabled in BIOS |
| HypervisorPresent (WMI) | False |
| systeminfo Hyper-V lines | Only 1 of 4 shown |

---
Exact Log Error

2026-03-22 15:38:58 [error] [VM:start] VM boot failed: HCS operation failed: failed to create compute system: HcsWaitForOperationResult failed with HRESULT 0x80370102: {"Error":-2143878910,"ErrorMessage":"The virtual machine could not be started because a required feature is not installed.","ErrorEvents":[{"Message":"Cannot create system 'cowork-vm' since Hyper-V is not installed on the host."}]}
2026-03-22 15:38:58 [error] [VM:start] HCS error detected, available=true, missing=[], sentinel=HYPERVISOR_SERVICE_ERROR
2026-03-22 15:38:58 [error] [VM:start] Startup failed: Error: HYPERVISOR_SERVICE_ERROR

Actual Behavior
Cowork shows virtualization error. The hypervisor does not launch at boot. The only workaround (bcdedit auto) causes a boot freeze on this hardware, making Cowork completely unusable.

---

Workarounds Attempted

• Enabled all Hyper-V Windows features ✅
• Updated BIOS from 0607 (2020) to 3201 (2025) ✅
• Deleted vm_bundles and claude-code-vm directories ✅
• Restarted CoworkVMService, vmms, vmcompute ✅
• Added --disable-quic electronArgs to config (fixed download, not VM launch) ✅
• bcdedit /set hypervisorlaunchtype auto → causes boot freeze ❌
• No conflicting virtualization software present ✅

Logs
%LOCALAPPDATA%\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\logs\cowork_vm_node.log

What Should Happen?

Cowork should detect that all Hyper-V components are installed and running, and successfully launch the workspace VM.

Error Messages/Logs

Steps to Reproduce

Steps to Reproduce

1. Install Claude Desktop v1.1.7714.0 on Windows 11 Pro (ASUS ROG Maximus XII Extreme)
2. Enable all Hyper-V features via Windows Features and PowerShell
3. Navigate to Cowork tab
4. Observe HYPERVISOR_SERVICE_ERROR
5. Attempt bcdedit /set hypervisorlaunchtype auto → system freezes at boot
6. Issue persists after BIOS update to latest version (3201)

Claude Model

Not sure / Multiple models

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.81 (Claude Code) Claude Desktop v1.1.7714.0

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

cowork_vm_node.log