Are you having issues logging into Windows 10 after completing an in-place upgrade from Windows 7 or 8.1? If so, keep reading. You may have already discovered that you are able to log in with an admin user successfully and the problem appears to only effect non-admin users.
Open the registry (Regedit.exe) and check the following 2 values. If either of these values are not set correctly, make the change and reboot the computer.
Shell = explorer.exe
Userinit = C:\WINDOWS\system32\userinit.exe,
My current Windows 7 workstations have the Microsoft App-V client installed, which adds Sftdcc.exe to the Userinit registry value. This is not cleared out during the Win10 in-place upgrade, so you are referencing a path that does not exist in Windows 10. This will cause the issue where a user tries to log in and will be immediately signed out.
This is an easy fix. You an either uninstall the App-V client during your in-place upgrade, or simply set the correct Userinit value during your upgrade by running the following command.
REG ADD “HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon” /v Userinit /t REG_SZ /d C:\WINDOWS\system32\userinit.exe, /f