If you often test or change operating systems you probably had situations where you want to make a copy of your entire hard disk drive to test your new settings or installations in a virtual environment.
Here is where you have a problem because you can’t boot your ISO hard disk image from CD-ROM.
You have to convert .iso file to .vdi file to be able to use hard disk image. Vdi file represents VirtualBox Hard Drive or Virtual Disk Image.
To do this use the following command:
VBoxManage converttoraw C:\path\to\iso\file\FileName.iso C:\path\new\vdi\file\FileName.vdi
Now when the conversion is finished you can assign your new virtual hard disk to a virtual computer. You can do this by adding a new (but existing) virtual hard disk drive to VirtualBox.
In a VirtualBox GUI select “New” to create a new virtual computer. Give it a name and select operating system you want to use. Then assign .vdi file you just created as computers virtual hard disk.
If you already have defined virtual computer, go to computer’s “Settings->Storage” and click “Add Attachment->Add Hard Disk” and select .vdi file you just created.