I just installed the Ubuntu-16.10-desktop-amd64.iso as a Virtualbox VM on my host system running KUbuntu 14.04. The install of 16.10 went flawlessly and the default Ubuntu login works fine, however, the only reason I installed 16.10 was to see what Unity8 looks like, as I stay on LTS versions only on my VM host system. When I try to login with the "Unity8" login at the greeter, my password is apparently accepted, the screen goes black for a moment, and then returns to the greeter. Not sure whats going on here....
Dave
Dave