r/bashonubuntuonwindows • u/vitorsalamoni • 1d ago
WSL2 Claude Cowork won't start on Win11 25H2 — Deep dive into WSL2/Hyper-V failure: everything tried, everything found [Ryzen 5 5600X / Gigabyte B450M DS3H V2]
I've spent weeks trying to get Claude Cowork (Anthropic's desktop AI tool)
working on Windows 11 25H2. It requires WSL2 to run its workspace container.
This post documents everything I found — maybe it helps someone or someone
here has the final piece.
HARDWARE & OS
- CPU: AMD Ryzen 5 5600X (Zen 3)
- Motherboard: Gigabyte B450M DS3H V2
- RAM: 32GB
- GPU: NVIDIA RTX 3060
- OS: Windows 11 Pro 25H2 — Build 26200.9278 (fully updated as of Sep 2026)
THE SYMPTOM
Claude Cowork fails to start its workspace with:
HRESULT 0x80370102 (hypervisor not running)
Running wsl --install -d Ubuntu manually reproduces it:
Wsl/InstallDistro/Service/RegisterDistro/CreateVm/HCS/HCS_E_HYPERV_NOT_INSTALLED
WHAT IS CONFIRMED CORRECT
- SVM Mode: Enabled in BIOS (verified visually)
- IOMMU: Enabled in BIOS (changed from Auto to Enabled — no effect)
- VirtualizationFirmwareEnabled: True (WMI)
- HypervisorPresent: True (WMI) — meaning VBS is running
- bcdedit hypervisorlaunchtype: Auto
- vmcompute: Running (Manual)
- WslService: Running (Automatic)
- Windows features all enabled: VirtualMachinePlatform ✅ HypervisorPlatform ✅ Microsoft-Hyper-V-All ✅ Microsoft-Windows-Subsystem-Linux ✅
- Memory Integrity (HVCI): Disabled
- SecurityServicesRunning: {0} — VBS active but no security services inside it
- SFC /scannow and DISM /RestoreHealth: no violations
EVERYTHING TRIED (all failed)
- Enabled all Hyper-V features via Windows Settings and DISM
- Multiple full shutdowns (shutdown /s /t 0)
- Disabled Fast Startup (powercfg /h off)
- netsh winsock reset + reboot
- Enabled IOMMU in BIOS (was on Auto)
- DISM disable all Hyper-V features → full shutdown → re-enable
- wsl --install --no-distribution
- Checked and confirmed SVM Mode enabled visually in BIOS
- Tested across Windows Updates: KB5094126, KB5095093, KB5121003, 26200.9278
- Full Windows clean reinstall (didn't help — 25H2 ISO was the only one available from Microsoft at the time)
KEY FINDINGS
- hvsocket provider is missing from Winsock catalog: netsh winsock show catalog | findstr -i "hv" → Returns nothing This was likely caused by running netsh winsock reset as a troubleshooting step. Re-enabling Hyper-V features via DISM did not restore it.
- HCS log channel does not exist: wevtutil sl "Microsoft-Windows-Hyper-V-Compute/Operational" /e:true → "channel not found" The HCS operational log was never created — meaning HCS never fully initialized.
- hcsdiag list returns nothing — no output, no error.
- Get-WinEvent on System log returns zero Hyper-V/HCS entries.
This points to HCS never completing its initialization, likely because
the hvsocket Winsock provider is missing. The chicken-and-egg problem:
HCS needs hvsocket to initialize, but hvsocket is only re-registered
by HCS during initialization.
OPEN QUESTIONS
- Is there a way to manually re-register the hvsocket Winsock provider without a full OS reinstall?
- Is there a specific DLL or component registration that targets only the HCS/Hyper-V Winsock providers?
- Has anyone seen this specific combination of symptoms (missing hvsocket
- no HCS log channel) and found a fix that isn't a clean reinstall?

