When working with virtual machines Kona prefers raw disk images. However, VirtualBox does not allow attaching raw disk images to virtual machines in its graphical user interface — trying to do so produces an error.

Could not get the storage format of the medium ‘' (VERR_NOT_SUPPORTED).

If you think youre clever you might fruitlessly try vboxmanage createmedium disk --format=VMDK --variant=RawDisk --property=RawDrive=…, but this doesnt work either. If theres a way to attach raw disk images using VirtualBox’s command line interface Kona is yet to find it. As a workaround user mpack in a forum post suggests manually creating and using a VMDK descriptor.

Since at least VirtualBox 7.2.4 there is a easier and more direct way:

1. Ensure VirtualBox is not running.
2. Find and open VirtualBox.xml in your favourite plain text editor. Its in $HOME/.config/VirtualBox, %USERPROFILE%/.VirtualBox, or $HOME/Library/VirtualBox.
3. Go to <VirtualBox> → <Global> → <MachineRegistry> → <HardDisks> while creating entries that dont exists.
4. Create a new <HardDisk> entry with attributes uuid with a fresh UUID, location with the path to your image, and format with raw — see example below.
5. Open VirtualBox’s graphical user interface and attach your raw disk image to your virtual machine.

<MediaRegistry>
	<HardDisks>
		<HardDisk 
			uuid="{00000000-0000-0000-0000-000000000000}" 
			location="<path to image>" 
			format="raw" 
			type="Normal"
		/>
	</HardDisks>
<MediaRegistry>

Why this is allowed nobody knows. If you do know please mention Kona on the fox’s Mastodon.