I would like to run hyper-v on a hyper-v server which in theory is possible. But when I try to start a VM in the child hyper-v I get an error. I checked the Event log and there it is, code 41. Hypervisor launch failed; Either VMX not present or not enabled in BIOS. We are running the host Hyper-V on an HP DL580 gen8 with 4x Xeon E7-4890 v2, 512GB Ram and 4TB accessible storage and 2x 10Gb Network.

So I've checked the BIOS and Virtualization is enabled, VT-d was enabled, I disabled it, because I read it on an old TechNet blog that U should disable it.

VT-x enabled, No-Execute Protection enabled, HT enabled, 0 Cores disabled and Power Management set to OS Controlled.

It did not made any difference that VT-d is enabled or not. The child Hyper-V always gives the same error. Oh and there is another error, if I manage the VM with Windows Admin Center when I click Virtual Machines I get an error notification that Powershell can't get CPU info, but in overview it shows the correct cpu and core count.

The child hyper-v is running in a Gen.2 VM if it makes any difference. Oh and both the Host and VM is Hyper-V Server 2019 (Core)

I read a loads of TN forum posts, blog entries about this error, but almost all suggest the same. Disable/Enable: VT, Trusted Execution, Disable Execute Bit... and turn off the machine and start up else the changes won't take effect. But this didn't helped me. How can I make this work?

  • "which in theory is possible." - ONLY on VERY specific INTEL chips. I am not sure an E7 v2 qualifies. Are you sure it is?
    – TomTom
    Nov 15, 2019 at 13:31
  • I think it qualifies. According to MS Intel CPUs with VT-x Support. That would qualify probably all consumer i7, i9 and I think all Xeon CPUs.
    – Laci K
    Nov 15, 2019 at 13:39

1 Answer 1


Did you try to expose the Virtualization Extensions to the VM?

Set-VMProcessor -VMName <VMName> -ExposeVirtualizationExtensions $true

Source: https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/user-guide/nested-virtualization

  • I did that. But now I disabled it with Set-VMProcessor -VMName <VMName> -ExposeVirtualizationExtensions $false and re enabled it. Now it works. Probably something got messed up while I was setting up replication for the Host or when I did a windows update. I don't know. Thanks I would never thought about this if you haven't post it.
    – Laci K
    Nov 15, 2019 at 13:44

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