Windows 10 login error - keeps signing out

I battled this problem for two months and giving admin rights was unacceptable at all since the machine i was working with was part of a library public computer. I did two things when fixing this issue and I'm not for certain which solution fixed it.

I checked the userinit string in the registery key "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon" and mine was "C:\Windows\system32\userinit.exe, C:\Windows\system32\SMchk.exe,"

I was a little confused about what the SMchk.exe was until I learned its a fortes grand process which is part of a time limit manager software we install. I replaced it with just "C:\Windows\system32\userinit.exe" and removed the trailing ",". After fixing the issue I still need to go back and re-enter the path to test it since we need that software to work. 

The other thing I tried was running Microsoft Account Troubleshooter and at first was skeptical that it would fix the issue since the guest account I was working with is not tied to a Microsoft account at all. But it does several other steps to fix and repair any issues. It did stop me mid way through the troubleshooter and said a Microsoft account was required to sync settings but clicking next skipped it and it continued on. Afterwards I removed the user from the administrators group and made it only a member of guests and logged off and back on and it worked perfectly. I did run this on the affected user and I'm not sure if that makes a difference or not but since it had admin rights at the time so what..

Hopefully this helps anyone with this issue and this thread has grown since i looked at it 2 months ago.

https://social.technet.microsoft.com/wiki/contents/articles/13976.how-to-troubleshoot-microsoft-account-issues.aspx