Why doesn't X64 OS support work in vritualBox?

Question

System administration

Good afternoon! There is a server on windows 2008R2, HyperV is spinning on it, 6 virtual machines are spinning on it. Here the task arose to install VirtualBox and transfer all the machines there with subsequent reconfiguration. Installed the latest version of VirtualBox, but when creating the machine, I can't create x64 OS. And in HyperV they spin without problems. What could be the reason? Take down HyperV and live on VirtualBox?
CPU

Answer 1

Does not work because there is no support for hardware virtualization.
Make sure it is enabled and no other hypervisors are running on the computer. Although two hypervisors on one computer, this is of course unlikely, but it's worth checking, it happens.

Answer 2

On ordinary machines (not servers) I observed this when the virtualization option was turned off in the BIOS.