Just throwing this out there, might absolutely not be related and me just missunderstanding whats actually happening here.
I had problems Imaging a computer at point when switching from a hdd machine as image-source to an ssd.
I had to change the host primary disk to the correct one - I think from sda to sda2 or something along those lines - for this to work.
Rereading again I suppose this is in another direction, but just in case.