The Red Devils have been on the hunt for a left-sided defender, even before the arrival of new boss Ruben Amorim.
Dimarco, who is 27, was seen as someone who could be a first team regular at United.
However, he is said to be very happy at Inter, where he has won the Serie A trophy.
Per Tuttosport, he has told any suitors that he is very satisfied with his present situation.
Inter also turned down United’s proposal, as they want to hold onto the defender.