Hello
Black screen may happen when the is no system volume (in Windows terms), i.e. the one that contains the boot loader. I suppose you haven't deselected volumes when starting the conversion?
Another possible reason is if the VM messes up the active partitions and tries to boot from the wrong one. Can you check whether your source machine has more than one active partition?
Anyway, waiting for the logs... Just a reminder - if you have converted "this local machine" the worker log is the interesting one, otherwise - it is the agent log.
Regards