While it should not matter (you have a file which contains a bootable system), in practise I only got it to work using a bootable hard disk. So you either have to tell Virtual Box it is a floppy, regular hard disk, or CD. It is not possible to tell Virtual Box you want to boot from a USB disk. 2.4 Mac does not fully unmount USB stickįreeBSD is distributed as a IMG file, which is a normal format for USB disks.2.3 Determine the mount location of the disk.2.1 USB2 is not supported by VirtualBox.