### Preflight Checklist - [x] I have searched [existing issues](https://github.com/anthropics/claude-code/issues?q=is%3Aissue%20state%3Aopen%20label%3Abug) 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? Impossible de démarrer l'espace de travail de Claude. failed to set session disk path: session disk not found: C:\Users\ \AppData\Local\Packages\Clau

[BUG] [Cowork] Windows 11 Home: sessiondata.vhdx never created, and 0x80370102 falsely reports VT-x disabled while firmware and OS both show virtualization enabled

Status Open

Reported on v2.1.219

Maintainer reply None cached

Workaround ✓ Mentioned in description ↑

Activity 0 comments · opened Jul 25, 2026

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?

Impossible de démarrer l'espace de travail de Claude.
failed to set session disk path: session disk not found:
C:\Users\<user>\AppData\Local\Packages\Claude_pzs8sxrjxfjjc\LocalCache\Roaming\Claude\vm_bundles\claudevm.bundle\sessiondata.vhdx

Name Size
---- ----
.auto_reinstall_attempted 0
.cowork-adopted 0
.initrd.origin 0
.initrd.zst.origin 0
.rootfs.vhdx.origin 0
.rootfs.vhdx.zst.origin 0
.vmlinuz.origin 0
.vmlinuz.zst.origin 0
initrd 0.07 GB
initrd.zst 0.07 GB
rootfs.vhdx 7.51 GB
rootfs.vhdx.zst 1.24 GB
smol-bin.vhdx 0.04 GB
vmlinuz 0.01 GB
vmlinuz.zst 0.01 GB
sessiondata.vhdx MISSING

Note the .auto_reinstall_attempted marker: the app's own automatic recovery already ran and did not resolve this.

Critically, the user cannot work around this on Windows Home. Creating a VHDX requires the Hyper-V virtual disk provider, which is not present on Home edition. diskpart create vdisk fails:

DISKPART> create vdisk file="...\sessiondata.vhdx" maximum=8192 type=expandable
Diskpart a rencontré une erreur : Impossible de trouver un fournisseur de prise
en charge de disque virtuel pour le fichier spécifié.

This is not an MSIX path-redirection problem — the same command fails identically when targeting a plain path such as C:\vhdtmp\. New-VHD is also unavailable, since the Hyper-V PowerShell module does not ship with Home. There is no supported path for a Home user to create this file.

Workaround that got past Defect 1: copy the existing valid VHDX from the same bundle under the expected name.

$b = (Get-Item "$env:LOCALAPPDATA\Packages\Claude_*\LocalCache\Roaming\Claude\vm_bundles\claudevm.bundle").FullName
$d = Join-Path $b 'sessiondata.vhdx'
Stop-Service CoworkVMService -Force
Copy-Item (Join-Path $b 'smol-bin.vhdx') $d
icacls $d /grant "$($env:USERNAME):(F)"
Start-Service CoworkVMService

Resulting file: 37,748,736 bytes. The "session disk not found" error disappeared — the disk was accepted. This confirms the only missing piece was the file's existence.

Defect 2 — 0x80370102 reports a firmware condition that is demonstrably false

With the session disk in place, startup now fails with:

Claude's workspace failed to start with HRESULT 0x80370102 (hypervisor not running).
Hardware virtualization (Intel VT-x or AMD-V) is disabled in this device's firmware.
Enable it in BIOS/UEFI settings and restart. On devices with a firmware password or
vendor management (Dell Command, HP BCU, Lenovo, vPro), this may need to be changed
via that tool.

What Should Happen?

sessiondata.vhdx should be created during bundle materialization, using a method that does not depend on the Hyper-V VHD provider, since that provider is absent on Windows Home. Home is a supported consumer edition and Cowork is marketed to non-technical users.

0x80370102 should not be reported as "virtualization disabled in firmware" without first checking HyperVisorPresent, hypervisorlaunchtype, and the CPUID virtualization bit. When those indicate virtualization is available, the message should say so and surface the real failing precondition.

On Home edition specifically, if Cowork requires Hyper-V components that Home cannot provide, this should be stated at install time as an unsupported configuration — not discovered after hours of user debugging.

A user-facing "Rebuild workspace bundle" action would have resolved Defect 1 in one click.

Error Messages/Logs

# Initial failure
failed to set session disk path: session disk not found:
  ...\vm_bundles\claudevm.bundle\sessiondata.vhdx

# diskpart, elevated, both inside the MSIX bundle path and in C:\vhdtmp
Diskpart a rencontré une erreur : Impossible de trouver un fournisseur de prise
en charge de disque virtuel pour le fichier spécifié.

# After supplying a valid sessiondata.vhdx
HYPERVISOR_VIRT_DISABLED

# UI
HRESULT 0x80370102 (hypervisor not running) —
"Hardware virtualization (Intel VT-x or AMD-V) is disabled in this device's firmware."

Steps to Reproduce

Windows 11 Home (Core) 25H2, build 26200.8875, MSIX / Microsoft Store install of Claude Desktop.
Launch Cowork. Bundle downloads and materializes — except sessiondata.vhdx.
Observe failed to set session disk path: session disk not found.
Attempt the obvious remedy: create the VHDX. diskpart create vdisk and New-VHD are both unavailable on Home. Dead end.
Copy smol-bin.vhdx to sessiondata.vhdx, grant the user Full Control, restart CoworkVMService, restart Claude.
Observe the first error is gone, replaced by HYPERVISOR_VIRT_DISABLED / 0x80370102.
Verify VT-x is enabled in UEFI, HyperVisorPresent is True, hypervisorlaunchtype is Auto, and both VirtualMachinePlatform and HypervisorPlatform are Enabled. Reboot. Error unchanged.

Reproducible on every launch.

Environment
OS: Windows 11 Home (Core), 25H2, build 26200.8875, x64
Feature pack: 1000.26100.334.0
Install type: MSIX / Microsoft Store (Claude_pzs8sxrjxfjjc)
Firmware type: UEFI ($env:firmware_type = UEFI); BIOS mode reported as CSM/UEFI
Motherboard BIOS: MSI E7C31IMS.160, build date 2024-07-09
CPU: Intel Core i9-9900K, 8 cores / 16 threads, 3.60 GHz — Intel Virtualization Technology: Enabled in UEFI
RAM: 32 GB
TPM: 2.0 (Intel PTT), firmware 303.12
Hyper-V role: not available on Home (Get-WindowsOptionalFeature returns no Hyper-V* entries)
WSL: not installed, so no same-hypervisor comparison was possible
VPN / third-party hypervisor: none active
Antivirus quarantine: checked, nothing related

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.219

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

The two defects compound badly. Defect 1 halts a Home user with no supported remedy. Working around it reveals Defect 2, whose message blames the user's firmware for a setting that is already correct. Between them, a non-technical user has no route to a working install and no accurate information about why.

Related reports, all Windows, all describing missing bundle artifacts or a missing sessiondata.vhdx:

#24974 — Windows: sessiondata.vhdx not created
#29657 — Windows 11 Home: bundle empty, rootfs.vhdx / sessiondata.vhdx missing
#24962 — Windows 11 Home: DNS misconfiguration, missing sessiondata.vhdx, no NAT
#32088 — CoWork VM fails after update, VHDX never downloaded

Windows 11 Home appears repeatedly in these reports. Given that New-NetNat is also unavailable on Home — see #24962 — it looks like Cowork's Windows implementation assumes Pro-edition Hyper-V components throughout.

UEFI setup screenshots showing Intel Virtualization Technology: Enabled, the TPM page, and the full bundle listing are available on request.

View original on GitHub ↗