When macOS High Sierra was released around 25^th 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.