Common Options : Enabled, Disabled

Details

This feature determines whether the BIOS will attempt to load an OS from the Second or Third Boot Device if it fails to load one from the First Boot Device. This feature is enabled by default and it's recommended that you leave it as such.

This will allow the BIOS to check the second and third boot devices for operating system on failing to find one on the first boot device. Otherwise, the BIOS will just halt the booting process with the error message No Operating System Found even if there's an operating system on the Second or Third Boot Device.