Former Manchester United coach Rene Meulensteen has said that the current side are suffering from "a lack of freedom" under Louis van Gaal.
Despite the fact that they are just one point off the top of the Premier League table, Man Utd have drawn criticism for their style of play.
Paul Scholes said that they were "disappointing" in their 0-0 draw with PSV Eindhoven, while captain Wayne Rooney said that they are not ruthless enough.
Meulensteen told BBC Sport that the problem lies in the "rigid" nature of their play.
He said: "The word is maybe 'rigid' at times.
"You see players where the ball could have been played forward with a little bit of risk, but they tend to go square or back. That's what the fans dislike at the moment.
"When Sir Alex Ferguson was at the helm there was a clear style and identity, but we also gave them the freedom to come up with their own solutions. There's a lack of freedom now."
Although Manchester United are unbeaten in their last eight outings in all competitions, they have found the back of the net on just six occasions during that run.