I have just noticed this as a result of trying to fix the group policy service, which dependant on MUP
therefore I don't know if it was always missing, happened in an upgrade

has anyone else had a similar experience, any ideas

there are suggestions online about how to "fix" by restoring mup.sys (in system32) to the services, but I'm a bit wary as there NOTHING on the official MS sites about this : not even the basic info on mup service