I now have this exact same problem on my third Surface Pro 4. This most recent one just did the same thing the first two did after leaving it sitting for two days. The process was the exact same:
-Turn on for the first time
-Go through initial setup
-pair pen
-Finally get in and do Windows Update
-leave for a day or two,
-start up gain and immediately goes into "Diagnosing your PC" "Attempting repairs" and "Automatic Repair couldn't repair your PC"
I haven't installed anything on the device other than doing the Windows Update and rebooting.
Any restarts after that immediately go into the same loop. EXTREMELY frustrating. I'm not sure how this made it out of QC. As I said, this is my third one in a row exact same symptoms as trauma2000 when trying repairs.