I am using Parallels access to connect to a Windows PC from my Mac. I'm on the same Wifi network as my target machine, and network connectivity is fine for all other software. However, my window on the Mac showing the Windows screen starts to 'flash' the image from when I first logged in for a moment, and then restores the screen. This happens more and more often the longer I'm connected. During the flash away, my keyboard still responds and whatever I've typed does get sent to the Windows machine. There is nothing in any logs for either machine.