The Frenchman signed for United in the summer of 2015 and made 44 appearances under Louis van Gaal, notably helping the side lift last year’s FA Cup at Wembley.
But the 27-year-old drifted to the periphery of the squad under current manager Jose Mourinho and was eventually sold to Everton in January.
In a recent interview with The Times, Schneiderlin revealed that he stopped attending games in December because it had become too “hard” for him.
“I will be honest, there was one point in December when I did not go to matches any more because it was hard,” he confessed.
“It was painful. I couldn’t go there, smile, and sign autographs for fans and pretend to be happy when I was not. For me it was better to watch the game at home.
“When I arrived at Manchester, the thing with the manager, with Van Gaal, I was not thinking as myself any more.
“I was thinking more like what he wanted me to do, and every time I arrived on a football pitch I was not thinking about what I could do when I get the ball. I was thinking what he wants me to do.
“There is a difference. When you think too much about things, that is when you start to miss things, like being late for a challenge.”
Since joining Everton in January, Schneiderlin has made 10 appearances for the club and is now enjoying regular first-team action.
The Frenchman’s form also appears to have returned having completed 89 per cent of his attempted passes in the Premier League with Everton.
Schneiderlin and his team-mates take on Burnley on Saturday as they continue to chase the prospects of European football.