Let’s say you have a dual boot system with a Windows 10 installation on 1 disk and a Linux installation on another disk. With Virtualbox, it’s possible to use the Windows 10 installation as a guest from within a Linux host. It works surprisingly well. These are the steps:

1. Create the raw disk image

For VirtualBox to use the physical hard disk instead of a virtual disk, we need to establish access it. This is done by creating a small .vmdk file that is linked to this hard disk. Use sudo fdisk -l to determine the drive name. Be carefull not to use your host installation, this will lead to unrepairable corruption.

sudo VBoxManage internalcommands createrawvmdk -filename /home/user/win10dual.vmdk -rawdisk /dev/sdb

2. Create the VM

For this to work, Virtualbox needs to started a root sudo VirtualBox. Add a new Windows 10 virtual machine as usual, but do not create a virtual hard disk. Instead, use an existing virtual hard disk file, add the vmdk we just created and select it.

Next we need to specify if Windows uses EFI boot or BIOS/MBR legacy boot

For better fullscreen support I disable the mini toolbar in Fullscreen / seamless mode.

Now we’re ready to boot!

3. Guest additions

Last step is to install guest additions.

Devices > Insert Guest Additions CD image…

Or download it from here, after selecting the right VirtualBox version.

4. Conclusion

Now we can use our dual boot Windows 10 installation as a Virtualbox guest in Linux. In fullscreen, with shared folders and everything. This was surprisingly easy to accomplish.

For more information, like mounting specific partitions instead of an entire hard disk. Look over here.