I am running Windows 10 on Parallels 12 on Sierra 10.12.6. I have an external drive and hardwired network connected through the USB-C ports. The USB-C ports drop connection at random times. If i suspend the Windows 10 VM they come back. As soon as i start the VM they drop again. I have to completely close the VM and then restart the MacBook. I then restart the VM and the ports are connected again. Has anyone seen this behavior with the setup i am describing? Let me know if you need any more information.