I have yet to successfully install the High Sierra beta, despite trying multiple betas over the months. I download the installer from the App Store and run it, it gives me the whole "installing helper" thing and tells me the computer will restart. It retarts, goes to the Apple logo, and then right back to the login screen. No error message or anything.
Any idea what may be going on?
That's not the problem I'm having. I have the current installer. My problem is that I'm trying to upgrade from Sierra to High Sierra, and even though it starts fine, it just reboots and brings me back to the login screen.
Genius. It worked. How did you figure that out?
I have the same problem, I also have Fusion Drive and have found exactly the same “unable to mount” log string.
To make things worse, now I can't even reinstall 10.12 from recovery partition because installer exits with an unspecified error.
