Check the last reply on my thread Unable to boot after installation (Dropping to a shell!) I think you may have the same problem which I did.
Your screenshot in the first post of that thread is exactly what I was getting. I'll reinstall in the next day or so when I have a moment and take a look at Grub at boot. I'll see if the fix in that thread works for me. and will try what @ryecoaaron recommends above: raid=noautodetect .
What is really strange to me is that I haven't used RAID in years. Not since @ryecoaaron recommended I try rsync instead of RAID quite some time back. Now I'm using Snapraid, so there's never been an array to assemble or reassemble, or have any other kind of issue with!