I had same problem after converting a physical compaq server
to vm.
Solution was :
As compaq server had a first small partition ( about 40mo ) for
his management, we didn't convert it to the vm.
This server had scsi drive with order for partitions.
Unable to boot the system after conversion.
Has SCSI order was not correct ( C: was not on 0 or 1 ... ),
I edited settings of my VM, and change the first drive to Second, the
second drive to the first ( change pointer to .vmdk ).
And tried to boot.
At a moment, my boot order was correct / SCSI order, and my
server stated.
Hope this can help you, give you idea.
Patrick.