For testing purposes, I have a VM in VirtualBox currently runnning macOS 10.12 Sierra. Now that macOS 10.13 High Sierra is in Beta, I wanted to upgrade my VM to this new release. However, this proved to be difficult with the usual ways. This blog post will describe how to upgrade a Sierra VM to High Sierra.
Upgrading a VM from macOS 10.12 Sierra to macOS 10.13 High Sierra in VirtualBox