Manchester United executive vice-chairman Ed Woodward admits they wanted to add more players to David Moyes' squad over the summer.
Moyes did not begin work until July 1, after United had opted against buying the Scot out of his Everton contract, reducing the time available to bring in new players.
As a consequence, Marouane Fellaini, who had been available for £23.5million prior to July 31, was the only significant purchase, and costing £4million more.
"It was disappointing that we didn't sign more players but I always knew it was going to be a tough window," Woodward told United We Stand.
"As a club, we didn't want to impose a plan on the new manager that had come from the old manager.
"I know other clubs have done that across the Premier League, where a director of football has bought players even before the new manager has arrived.
"That happened very close to home.
"We didn't want to do that. We have a manager who we want to give our full support to make his decisions about the players and the decisions about the academy.
"He has the same power that Alex did."
