Fans of the sci-fi shooter Halo will have to wait until later this year for the sequel to the best-selling game.
Halo 2 promises more action and weapons and better graphics
Many had hoped Halo 2 would be out by spring, but developers Bungie have confirmed that it will not be ready until the autumn.
"Now we're confident. Halo 2 will ship in fall, 2004. Please make a note of it," the company said on its website.
The award-winning Halo: Combat Evolved has sold more than four million copies to date.
The original Halo came out with the launch of the Xbox in November 2001, going on to become the console's must-have game.
When Microsoft announced a sequel two years ago, it said the game would be shipped at the end of 2003.
But the game missed the festive season and was widely expected to be out by the spring, or summer at the latest.
Halo has sold four million copies worldwide
However fans of the adventures of the genetically enhanced super-soldier called Master Chief face a longer wait.
The delay announced by Bungie on its website has been confirmed by Microsoft.
A spokeswoman for the software giant said Halo 2 was now set for release in the later part of the year, though a firm date was not available.
Bungie is promising more action and weapons, better graphics and a multi-player option to face other gamers on Microsoft's Xbox Live service.
"Here at Bungie.net, as you've recently witnessed, we're ramping up a campaign of new content, details and snippets of info, just to keep you sated while you get ready for fall," said a note on its site.
The developers will offer fans a taste of Halo 2 at the video game industry's main trade show, E3 in May in Los Angeles.