Hyper-V cannot be installed because virtualization support is not enabled in the BIOS

Question

I am trying to enable Hyper-V on an Azure VM E4as_v6 running Windows Server 2025 Datacenter Azure Edition.

The spec sheet found at https://learn.microsoft.com/en-us/azure/virtual-machines/sizes/memory-optimized/easv6-series?tabs=sizebasic indicates nested virtualization is supported.

The VM is provisioned with a Security Type of Standard.

When I use the server manager to enable Hyper-V I receive an error message that reads: Hyper-V cannot be installed because virtualization support is not enabled in the BIOS

What steps do I need to take in order to enable Hyper-V?

Answer 1

Hi Jorge,

Thanks for your question. Welcome Microsoft Q&A

You're absolutely right — the E4as_v6 VM does support nested virtualization, but by default, this feature is not enabled on newly created VMs in Azure. The error you’re seeing:

"Hyper-V cannot be installed because virtualization support is not enabled in the BIOS"

…means nested virtualization hasn't yet been explicitly turned on for the VM.

1. Nested virtualization only works with VMs using a hypervisor-compatible image, such as Windows Server Datacenter editions.
2. Ensure the VM SKU (like E4as_v6) and Gen 2 VM settings are in place. Gen 2 is required for some advanced scenarios.

Try first this script in a test machine:

Azure CLI

az vm stop \
  --resource-group <YourResourceGroup> \
  --name <YourVMName>

az vm update \
  --resource-group <YourResourceGroup> \
  --name <YourVMName> \
  --set hyperVGeneration=V2 \
  --set additionalCapabilities.enableNestedVirtualization=true

az vm start \
  --resource-group <YourResourceGroup> \
  --name <YourVMName>

💡 Replace <YourResourceGroup> and <YourVMName> with your actual values.

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