Hi @VEDRINEN , Parallels Desktop 10 for Mac is not compatible with mac Os High Sierra. Please check this article to know the Host Os compatibility for Parallels Desktop for Mac.
Well, that is not really correct because I actually use 3 VM on my High Sierra Mac :
an Ubuntu machine
a Window 7 machine
a Yosemite machine
Each has been installed before I upgrade to High Sierra and everything works fine. So It is just when I try to install a fresh new one when the boot sequence fails.
In parallel, I install a fresh new High Sierra machine on a hard drive instead of a VM. Maybe I can clone that install in a new VM to fix the boot sequence ?