The Spaniard left United in 2019 for Paris Saint-Germain, who offered him a contract on higher wages.
Herrera, who was hugely popular with the United supporters, felt that disagreements with the board led to his United departure.
"When I look back a year ago, my intention was not to leave Manchester United," Athletic Bilbabo veteran Herrera told to ESPN.
"I had some different opinions with the board but I respect them."
"I respect them a lot. They do things for Manchester United and I disagree with the people who say they don't. They really suffer when things don't go well and they really fight to bring Manchester United back. I disagreed with some of the decisions they made but this happens in football. It happens in every company.
"Apart from that, I respect them. I had a great relationship with (former CEO of United) Ed Woodward and with the owners when they came, so I have nothing to complain about with them."