Lots of people are having this problem. Looks like api-ms-win-core-libraryloader-l1-1-1.dll is a Windows 8 File it is not from Windows 7.  Simply navigate to C:\Windows10Upgrade\wimgapi.dll after you change folder options to unhide files.  Change wimgapi.dll to wimgapiold.dll , then navigate to: C:\Windows\System32\wimgapi.dll and copy it, then paste to  C:\Windows10Upgrade\wimgapi.dll “Restart the Upgrade”.

The upgrade now works perfectly.