Windows 10. Parallels 12.2.1. MacOS 10.12.5. MacBook Pro 15" (2017) Retina. Windows looks horrible under Parallels. The setting View > Retina Resolution produces no good or persistent results, regardless of the option Best for Retina Display, or Scaled. The view changes every time I launch the VM. Sometimes the icons are tiny, sometimes huge, sometimes the text in apps is all grainy and unsharp, sometimes perfect. All I want is a view that is the SAME every time I boot Parallels / Windows. Every time. I have no idea what the heck Parallels is playing around with, but it's almost like the VM is randomly configured into a different display situation with every reboot. The ONLY way I've found to get what I want is to turn OFF this "custom scaling" after I boot Windows and then reboot. Doing so produces a good display, but it takes up to 15 minutes for Windows to reboot and settle down. And then the next time I launch the VM, Parallels has gone and f'd with the settings and I have to start over.