The Red Devils have come in for plenty of criticism for their unadventurous style of play in recent months following their stuttering form this season.
Van Gaal’s side have won only two of their last 10 Premier League games to leave them five points adrift of the top four heading into the final 15 matches of the season.
United returned to winning ways with a 3-1 victory at Derby County on Friday night as they booked their place in the fifth round of the FA Cup.
But former Arsenal striker Henry feels that most of United’s supporters are throughly unimpressed by the brand of football the Red Devils have been playing this season.
Writing in his column for The Sun, Henry said: “I know a lot of United fans and all they talk about is how poorly their team are playing. It’s not about results any more.
“Even when they win, the issue is still how awful the football is. They don’t enjoy watching their team any more. They are bored.
“How can it even be possible they have managed just 35 shots on target all season in the Premier League? And 11 consecutive league games without a single first-half goal? It is unbelievable.
“It has reached the point where the manager’s future is up for debate after every game.”
United finished fourth last season but were dumped out of the Champions League at the group stage last month.
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