Nested Virtualization not working anymore


Active Member
Aug 24, 2018
Hello there

i Upgraded my Proxmox and now my Nested Virtual Windows Server 2016 do not start anymore..

Come to the Windows Logo and then the Machine does a reset...

if i change the CPU to the Default (kvm64) then it starts, but the hyper-v machines can not run...

cat /etc/modprobe.d/kvm-intel.conf
options kvm-intel nested=Y

cat /sys/module/kvm_intel/parameters/nested

Can you please help me?
Hi Dominik

What for Info do you need?

cat 120.conf
bootdisk: ide0
cores: 2
cpu: host
ide0: HS-Only:120/vm-120-disk-0.qcow2,backup=0,replicate=0,size=80G
ide1: WinServerDisks:120/vm-120-disk-0.qcow2,size=5G
ide2: WinServerDisks:120/vm-120-disk-1.qcow2,size=5G
ide3: WinServerDisks:120/vm-120-disk-2.qcow2,size=10G
memory: 3072
name: WinServer2016EVAL1
net0: e1000=6A:DE:DF:14:C5:E3,bridge=vmbr0
numa: 0
ostype: win10
scsihw: virtio-scsi-pci
smbios1: uuid=1ae02cb2-0b86-4171-935f-7b5adee398d5
sockets: 1
virtio0: WinServerDisks:120/vm-120-disk-3.qcow2,size=10G
vmgenid: ce194491-f1f7-4b7d-9b8f-b7959dbc0d67
whats you pveversion and did you try a different version of windows server already?
pve-manager/5.3-5/97ae681d (running kernel: 4.15.18-9-pve)

What do you mean with different Version?

I Try a New Test Install from Windows Server (Same ISO), and the reinstall works... But i need the current installation, there are my configuration on it.
you could try to see if using an older machine type works, e.g. 2.11
qm set VMID -machine pc-i44fx-2.11
Hi, get an Error with this command:

qm set 120 -machine pc-i44fx-2.11
400 Parameter verification failed.
machine: value does not match the regex pattern
qm set <vmid> [OPTIONS]
sorry it is pc-i440fx-2.11
That's working thank you. Can you explain me what we did with this command?
thank you!
it sets the qemu machine type to the version which is used in qemu 2.11, maybe there were some changes which are incompatible with hyper-v
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