Having been scheduled to arrive at North American retail earlier this week, Microsoft has admitted that it has postponed the release of the Vista version of Halo 2 due to an “obscure content error” involving some sort of nudity.

In a statement to Next Generation, Microsoft confirmed: “It has come to our attention that an unfortunate, obscure content error which includes partial nudity was included in our initial production of Halo 2 for Windows Vista.

“As such, we have updated the initial game packaging at retailers with a label, so customers are aware before purchasing the game. Additionally, we’ve developed an online update which can be downloaded from www.halo2.com to remove the content.

“At Microsoft we take the Entertainment Software Ratings Board guidelines very seriously and hold ourselves to high standards, with our customers always in mind.”

The nature of the content still remains a mystery.

The news will strike a chord with US anti-games campaigners who were up in arms following last year’s discovery of hidden adult content in Rockstar’s Grand Theft Auto: San Andreas.