How to make a bootable USB flash drive start a virtual machine in Virtual Box?

Instead of installing Windows from an ISO image, or from physical optical media in your CD drive, you can boot Virtual Box with a pen-drive, just like you format your own machine, to start the system, however, it is not trivial and there is no native support.

In this tutorial, we will explain how to create a virtual disk that points to your pen-drive, so you can use it as a secondary hard disk, and boot as you wish, as well as use and edit the disk within the operating system.

First, you need to download VirtualBox on your computer, with at least version 5.0, and install the extensions, on the website http://virtualbox.org/

After installed, look in Disk Management, with the pen-drive with the operating system to boot, which is the device number, as below, Disk 2: 

You can quickly access the manager by typing "partition" in the start menu:

This action below, does not erase the pen drive, although it takes a few minutes to execute, and creates a virtual disk as a bridge to access your pen drive directly:

vboxmanage internalcommands createrawvmdk -filename c:\usb.vmdk -rawdisk \\.\PhysicalDrive2

See the result above. Copy the file and copy it to the virtual disk folder, and make sure to set the correct privileges in the security tab so that the program can read the file.

Boot the Windows installation from the flash drive to the virtual machine.