I'm going to note an app. THIS IS NOT TO SAY THIS IS WHAT IS GOING ON but to share there are legitimate apps that can do this. Example:
" Reboot Restore Rx™ is a Freeware utility that makes it easy to maintain PC’s in small public access

computing environments (classrooms, computer labs, kiosks, internet cafes, libraries, etc.). Every time you restart the PC’s - they will automatically reset to your desired baseline settings."

So there we have apps that can cause this. I don't know your PC or if you share it.

---> If this was mine I'd create a NEW LOCAL LOGIN ACCOUNT and then use that to see what happens in a NOT AN EMAIL BASED LOGIN. Here's a note about that:
http://www.howtogeek.com/226540/how-to-create-a-new-local-user-account-in-windows-10/