The Donegal manager arrived but left a minute later after consulting with GAA communications staff.
The Croke Park officials then approached Gaelic Life reporter Declan Bogue who was told that McGuinness would not conduct the press conference if he remained in the room.
Bogue, who penned the controversial book ‘This Is Our Year’ which featured interviews with Kevin Cassidy, then left the room.
McGuinness soon returned and agreed to continue with the press conference.
McGuinness said he had kept his counsel on his feelings about the book all year and had waited until now to make them known.
“There was a book written,” he said. “There were a lot of untruths in the book. There was a lot of things said about me. I’ve never broken court on it since the whole thing happened. I’ve held my dignity. I’ve let myself be castigated. And I done that because I gave somebody an agreement that I wouldn’t break my court on it. There were a lot of things said in the book that were incorrect and untrue, some of it possibly lies about me personally and about some of my players.
“It was all-out attack for a couple of months on my character. I know what I’ve done, I know what I’ve coached, I know what I am as a person. And that’s the situation. So I’m not going to let somebody sit in a room and fill their pages tomorrow on the back of what we done today when they in their wisdom degraded me as a person and some of my players.”