You can select the firmware type of a virtual machine.

The following firmware types are available depending on the guest operating system.
Option Description
UEFI Unified Extensible Firmware Interface (UEFI) is an interface between the operating system and the platform firmware. UEFI has architectural advantages over Basic Input/Output System (BIOS) firmware.
Legacy BIOS Standard BIOS firmware.
If you select UEFI, depending on the guest operating system, you might have the option of enabling UEFI Secure Boot. UEFI Secure Boot secures the boot process by preventing the loading of drivers and operating system loaders that are not signed with an acceptable digital signature.


  1. Select Window > Virtual Machine Library.
  2. Select a virtual machine in the Virtual Machine Library window and click Settings.
  3. Under Other in the Settings window, click Advanced.
  4. Select an option from the Firmware type menu.
    If the firmware type is not selectable, look for an explanation and, possibly, instructions at the bottom of the dialog box.
    • Once a guest operating system is installed, changing the firmware type might cause the virtual machine boot process to fail.
    • If virtualization-based security (VBS) is enabled, the firmware type is set to UEFI and cannot be edited.


When you start the virtual machine, it boots with the selected firmware configuration.