The Catalans replaced Koeman with Xavi Hernandez mid-season after a disappointing string of results.
Ronald Koeman has criticized Barcelona president Joan Laporta for his poor strategy in talking to the media.
The Dutchman has repeatedly hit out at Laporta since his departure from the Catalans last season. The Barcelona president started looking for a new coach while Koeman was still in the dugout.
He eventually persuaded Xavi Hernandez to take charge at Camp Nou. But Koeman says Laporta should be blamed for his ugly end to his time at the club.
“Leaving was a bit of a liberation,” he told TV3. “It was a difficult time for the club, first without a president, then with Laporta’s doubts about the manager.
“You want to be a coach but you know that if you don’t win, you have problems.
“As president, you can always have doubts. But if you say them to the public, everyone starts to doubt. It was a big mistake on his part.”
He added: “In general, the dressing room was not against the coach.
“We worked well. The problem was when the president came. A president or technical director can doubt the coach, but the problem is that it came out in the press.
“As president, you cannot leave doubts about the coach. I would never do that. I show my face and go straight ahead.”
Koeman has reached an agreement to become Netherland‘s new manager after the World Cup. The former Barcelona boss will take over from Louis van Gaal, who is struggling with illness.