“Hyper-V cannot be installed: A hypervisor is already running” message in Vmware Workstation

by
  1. First, shut down the virtual machine.
  2. Make certain that you’ve enabled VT-x/EPT in your virtual machine.
  3. Modify the vmx file associated with your virtual machine and add the following lines to the end of the VMX file:

    hypervisor.cpuid.v0 = “FALSE”
    mce.enable = “TRUE”

  4. Restart your virtual machine.