Louis van Gaal claims Manchester United chief executive Ed Woodward has "zero understanding of football" and the club is suffering as a result.
The 67-year-old former United manager, who also had spells in charge of Ajax, Bayern Munich, Barcelona and Netherlands, blames Woodward for most of club's struggles since he was sacked in 2016.
"At Bayern, the people in charge are football men. I always appreciated that," Van Gaal told German magazine 11 Freunde.
"At Manchester United, on the other hand, Ed Woodward was installed as CEO - somebody with zero understanding of football who was previously an investment banker.
"It cannot be a good thing when a club is run solely from a commercially-driven perspective."
He was replaced by Jose Mourinho, who was also sacked in December 2018, but Van Gaal understands why the club appointed the former Chelsea boss.
"I don't hold it against the club. They wanted Mourinho and he was on the market," the Dutchman added. "Appointing him was obviously interesting from a business point of view.
"He wins games and for a club like United, the main thing is to win trophies. How they are won isn't the main priority, the English fans see it differently.
"They accept that the game is not all about attacking but it is also about defending. I always tried to defend high up the pitch, to be in the opposition's half and play the game there."