Mourinho's time at Old Trafford has been littered with allegations of fallouts with his players, the most prominent of which has been his ongoing feud with France international Paul Pogba.
Results on the pitch have suffered too, with United failing to win any silverware last season and making their worst start to a league campaign since 1989-90 so far this term.
The Mirror reports that a number of players believe Mourinho has undermined the team spirit and confidence with his regular criticism of certain players and the team's performances.
The report - citing a source close to the dressing room - goes on to say that the players feel inhibited by the negative atmosphere created by Mourinho and are tired of the manager shifting the blame for poor performances elsewhere, instead of assuming it himself.
United are winless in their last four games across all competitions heading into Saturday's home Premier League match against Newcastle United.