If, like me, you use Parallels Desktop Lite, then I have bad news for you. It's no longer free to run macOS or Linux, so DON'T update it if you still want to use it!
I got macOS Mojave 10.14 / 10.14.1 installed in Parallels very easily! But encountered some graphics issues with certain apps... and managed to find a workaround.
When macOS High Sierra was released around 25th September, I tried to install it in Parallels Desktop Lite. However, both a clean install in a Parallels Virtual Machine (VM), nor an in-place update did not work (the High Sierra VM would refuse to boot). I discovered the High Sierra installer converts the VM file system to Apple File System (APFS). However, Parallels does not support APFS, so here's how to disable the conversion and get High Sierra running in a Parallels.