The Athletic Bilbao star was the subject of a bid from the Premier League power, but the Liga outfit insisted a sale would have to require Man Utd triggering a release clause.
The 24-year-old Herrera was one of a number of central-midfield targets Moyes failed to lure to Old Trafford, with Thiago prefering Bayern Munich and Cesc Fabregas opting to stay at Barcelona.
Moyes has confirmed an offer for 23 million pounds was lodged, but Athletic Bilbao was only prepared to part with the talisman if his 30.6 million pound release clause was triggered - demands the United boss deemed unsuitable.
"The stuff about Herrera, we made an offer for 23 million pounds, and we were never going to go to the buyout clause," Moyes told reporters. "All the rubbish that was talked about that - with people going in, they were never working on behalf of us. Never at any time did we increase our offer."
Moyes, though, was bullish when questioned on his other failed attempts at recruiting players, and insisted that Marouane Fellaini, who joined in a deal worth 27.5 million pounds on deadline day, was always in his mind, with a pursuit of Leighton Baines preventing earlier confirmation.
"Did we miss out on a lot of targets? No. Was it disappointing? No. We tried to get some great players to join Manchester United and for different reasons we couldn't get them," Moyes said. "In the end we knew at the start of the window that we liked Marouane Fellaini, you've heard my explanation on why we didn't do it sooner."