Ferguson believes he simply took the competition too lightly last season given that United usually sail through the group stages. But last term they won only two games of their six and went out after an away defeat to Swiss side Basel.
Ferguson said: "That definitely won't happen next season, there is no chance of that.
"Over the last few years we have used the group stages in Europe as an opportunity to play some of the youngsters.
"We have done it two or three times - but last season it backfired for us.
"We changed the team too much and we won't be doing that this season."