What I have: iMac 27" 5K (Radeon Pro 580 8 GB) MacOS 10.13.1 Parallels Desktop 13.1.1 Ubuntu 16.04 LTS virtual machine Latest Parallels Tools installed in Ubuntu successfully. The problem. The highest resolution I get in Ubuntu is 2560x1440. Retina Resolution setting in Parallels Desktop is set to "Scaled" and it is scaled very well, but I don't have clear graphics, it's really blurry. If I switch Retina Resolution setting in Parallels Desktop to "More Space", Ubuntu gets 5120x2880 resolution, I can see more clear text and graphics, but all interface elements become super small, really impossible to use. Yes, I can go to Ubuntu Screen Display settings and increase scale for menu and title bars, increase font sizes, but some applications won't scale and look awkward. The result I look for: I need 5120x2880 resolution in Ubuntu but it should be scaled normally, like it's 2560x1440. Just the way it works in Mac OS, and it does work this way if you run Windows X in Parallels Desktop (it's scaled well and it's very clear). Right now I have to use blurry Ubuntu, because I need all applications to display correctly without forcing it to scale using Ubuntu.