Virtualization is not available - showing in Claude Desktop - Cowork

Question

Virtualization is not available - showing in Claude Desktop - Cowork

OKADA 0

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I'm on a VM , Standard B4as V2 ( 4 - 16 GB )
I installed Claude Desktop but Cowork is not running well with this error.

Anyone can help?

Adithya Prasad K 1,395 Reputation points Microsoft External Staff Moderator

2026-07-01T18:08:13.8866667+00:00
The error is expected in this setup because the VM size being used is Standard_B4as_v2, and the Basv2-series does not support Nested Virtualisation. Microsoft Learn lists Nested Virtualisation = Not Supported for the Basv2 VM family, and Standard_B4as_v2 belongs to that Basv2 series. [learn.microsoft.com]

Claude Desktop / Cowork requires hardware virtualisation / Hyper-V support inside the Windows VM. Since this is already an Azure VM, the Azure VM size must support nested virtualisation so that Hyper-V / Virtual Machine Platform can run inside the guest OS. Internal Azure support guidance also states that nested virtualisation requires a supported VM SKU/series, with examples such as D_v3 / Dv4 families, and that the virtualisation extensions must be exposed to the VM. [Troublesho...n in Azure]

Root cause

The current VM size Standard_B4as_v2 is a burstable B-series v2 SKU. This SKU is suitable for low-cost general workloads, but it does not expose nested virtualisation capabilities. Therefore, enabling Hyper-V / Virtual Machine Platform inside Windows will not be sufficient while the VM remains on this size. [learn.microsoft.com]

Recommended resolution

Please resize or redeploy the VM to a SKU that supports nested virtualisation, for example a supported D-series / DS-series / E-series / F-series SKU depending on availability in your region. For a similar 4 vCPU / 16 GB profile, you may evaluate sizes such as:

Standard_D4s_v3

Standard_D4s_v4

Standard_D4s_v5

Standard_E4s_v5 if more memory headroom is required

Before resizing, please validate SKU availability in the target region:

az vm list-skus \

--location <region> \

--resource-type virtualMachines \

--all \

--output table

Then stop/deallocate the VM and resize:

az vm deallocate \

--resource-group <ResourceGroupName> \

--name <VMName>

az vm resize \

--resource-group <ResourceGroupName> \

--name <VMName> \

--size <SupportedNestedVirtualizationSKU>

az vm start \

--resource-group <ResourceGroupName> \

--name <VMName>

After moving to a supported SKU, enable the required Windows components inside the VM from an elevated PowerShell window:

Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All

Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform -All

Enable-WindowsOptionalFeature -Online -FeatureName HypervisorPlatform -All

bcdedit /set hypervisorlaunchtype auto

Restart-Computer

After the restart, verify whether Hyper-V is detected:

systeminfo

Look for Hyper-V requirements / hypervisor status. If the VM is now on a supported SKU and Windows features are enabled, Claude Cowork should no longer fail because of missing hardware virtualisation.

Important note

If the VM was created with Trusted Launch, please validate compatibility for the specific nested virtualisation scenario. Microsoft troubleshooting guidance for nested Hyper-V rescue VMs recommends using Standard security type because Trusted Launch can block Hyper-V installation in that scenario. [Troublesho...n in Azure]

If the issue continues after resizing

If the VM is moved to a supported nested virtualisation SKU and the Windows features are enabled but Claude/Cowork still shows the same message, then the Azure VM side is likely configured correctly and the remaining issue may be with the Claude Desktop/Cowork application detection or service. In that case, collect:

Then share the outputs with the Claude / application vendor support team for further validation.

1 answer

Your answer

Answer 1

Hi @OKADA

Directly we cannot to access BIOS so, enable nested virtualization

from Azure CLI locally or cloud shell.

az vm update \
  -g YourResourceGroup \
  -n YourVMName \
  --set "additionalCapabilities.enableNestedVirtualization=true"

Stop the VM

Start the VM (not restart — full stop/start is required)

After this, Windows inside the VM will detect virtualization.

from powershell

Inside the VM:

Enable Hyper‑V

  Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Hyper-V -All

Enable virtualization platform

  Enable-WindowsOptionalFeature -Online -FeatureName VirtualMachinePlatform

Ensure Hyper‑V is active

  bcdedit /set hypervisorlaunchtype auto

Thanks.