Windows Vista 1013 Published by

Microsoft CEO Steve Ballmer said that Longhorn, the much delayed Windows OS that was released as Windows Vista in 2007, was "the single biggest mistake I made."

From Neowin:
Mary Jo Foley conducted what may be Steve Ballmer's final press interview while he is still CEO of Microsoft in late November. The major parts of that chat were posted today at CNN's Fortune website but Foley has some expanded portions of her chat with Ballmer on her ZDNet column today as well.

In one of those columns, Ballmer expanded on his own previously admitted regrets over the treatment of Longhorn, the code name for the Windows XP successor that eventually was released as Windows Vista in 2007. Ballmer is quoted again today about the Longhorn-Vista efforts, saying, "That was the single biggest mistake I made."
  Steve Ballmer: Longhorn-Vista was the "single biggest mistake I made" as Microsoft CEO