1. Create server template from server VM (so it's a full copy of the
disk)
2. From template create a VM, override server to desktop, so that it
become a qcow2 overlay to the template raw disk.
3. Boot VM
4. Shutdown VM
5. Delete VM
Template disk is now corrupt, any new machines made from it will not
boot.
I can't see why this happens as the desktop optimized VM should have
just been an overlay qcow file...