D: As we have performed a clean installation of Windows 10 without formatting the drives, User1's Windows 8.1 user profile will be located in the \Windows.old folder. Therefore, we need to run scanstate.exe on the \Windows.old folder.
E: User1's Windows 10 profile will be in the C:\Users folder so we need to run loadstate.exe to apply the changes in the C:\Users folder.
Reference:
https://docs.microsoft.com/en-us/windows/deployment/usmt/usmt-how-it-works
https://docs.microsoft.com/en-us/windows/deployment/usmt/usmt-common-migration-scenarios#bkmk-fourpcrefresh