I'm trying to create a VirtualBox image of Windows 8 Consumer Preview. I did exactly what was said in this tutorial, but at the step "Now navigate to the Windows 8 developer build ISO file that you downloaded and select it" I get the following error:
Could not get the storage format. (VERR_NOT_SUPPORTED)
I also get this if I use the regular wizard. I'm using VirtualBox version 4.1.16 on Windows 7. It happens with both 64-bit and 32-bit Windows 8 as the guest OS.