No result and I still can't work ! They send me message that they passing my ticket to next level of support: Hello Piotr, Thank you for contacting Parallels Support. From our conversation, we understand that you are unable to start Windows virtual machine when Nested virtualization is enabled. Thank you for your patience and cooperation while we are working on the resolution. Together we have tried to resolve the issue using a number of possible troubleshooting steps, however were not able to succeed yet. Since the issue requires a deeper investigation, I am passing your ticket to our next level of support who will follow up with you on your request directly.