Create a VM from a Disk

Hi

I've done a lot of searching and reading in this forum and within MS and I (unfortunately) think I know the answer but I'll ask it anyway just to get closure:

Is it possible to create a VM from an unmanaged disk, either in PowerShell or the ARM portal ? From everything I've read it seems it can only be done with managed disks (currently our management have decided not to use managed disks before anyone asksJ ).

Thanks