Odd Whonix Gateway boot (into grub rescue)

So, I received this when kicking up Whonix Gateway 9.6:

OS is Linux Mint 64 bit, running VirtualBox 4.3. Verified both my VirtualBox and Whonix downloaded correctly. Only modification made to the default gateway import was to set 256MB RAM to get the command line version instead of a desktop. Tried doing it without changing RAM to no effect. Nothing obviously wrong anywhere else that I can think of either.

Those modifications are fine. Very, very unlikely to be related.

It only happens on that machine? On other machines, you can use Whonix?

Either way, I am afraid to say, that I have no clue what could cause this.

Only on that specific machine. No problem running other virtual machines of any kind either. Very strange.

Will try running another OS on the same hardware and see if that makes any difference.

Worth trying would also be testing Debian wheezy inside that VirtualBox.