As we prepare to move to Office365 we're going to start pushing our users to login with their UPN in the format of first-last@domain.com to match our email addresses.
When we login on a windows 7 or windows 8 machine using UPN the credentials used seem to be properly recognized.
We can check HKLM\Software\Microsoft\Windows\CurrentVersion\Authentication\LogonUI\SessionData and verify the key LoggedOnUser is recognized as first-last@domain.com. However on Windows 10 the same registry key is changed and matched the LoggedOnSamUser matching domain\user format.
Our domain and forest functional levels are at Windows 2003
Rkaram
