Start Menu left click does not show start menu on Windows 10 and Server 2016.
Import registry key HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Appx\AppxAllUserStore from a working server without this start menu issue.
UPM 7.15.2000 and 7.17 caused to delete registry keys HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\AppReadiness and HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Appx\AppxAllUserStore