Mourinho expects a "nice reaction" from the United home support on his return, but says the Old Trafford crowd will "forget" him when the match kicks off.
He said: "I'm not a villain, I'm not an enemy but I am the coach that is trying to win against Manchester United. That's the way I think they are going to look at me.
"(Ole Gunnar) Solskjaer is the guy that is trying to win the game for United fans so of course they are going to support him and not support me.
"I think a nice reaction is probably to me but then during the game the support will be for Solskjaer. They love their club, so they love Solskjaer.
"During the match I expect them to forget me and to support their team to get the result they want."