A £63million fee had been agreed with the Spanish club to bring him to Old Trafford.
But agreeing personal terms proved too difficult, with the 25-year-old determined to stay with the LaLiga giants.
He later added that at times during the summer he and Barcelona did not always agree on where he would be playing his football this season.
"I can't give too much details away," he said. "But look.. the club has it's own ideas and I have my own ideas too and sometimes this clashes with each other. But at the end of the day things went okay."