halszkaraptor

I had this same thing happen to me, following the same set of steps also on 6.8.3. After enabling the options, and editing the XML, I booted the VM and turned on Hyper V features in windows. When it attempted to reboot, and on all subsequent boot attempts, the VM would not boot and was stuck on the Tiano Core screen. After going through a ton of posts on the forums, and none of the solutions working, I found this open report [6.8.2] NESTED HYPER-V NOT WORKING, which seems incredibly similar. I decided to try and downgrade to 6.7.2 but got as far as 6.8.2 and the GUI provided no option to downgrade again. So, I decided to boot the VM just to see what it did on 6.8.2. To my extreme surprise, the VM booted just fine into windows and everything is working. I unfortunately do not have any diagnostic information, but wanted to report another occurrence of this issue.