Microsoft has delayed the launch of Vista until January 2007. The company still plans to release Vista to business partners through its volume licensing programme in November 2006 but PCs with Vista pre-installed will not be available until the following year.

Microsoft co-president of the platform and services division, Jim Allchin said that Microsoft wanted to give customers a firm date for when the company could deliver Vista broadly, and so decided to push back the release to January. Earlier this year, Allchin indicated that he would delay releasing Vista if the OS did not reach a standard of quality with which he was comfortable

In November, Microsoft still plans to release to manufacturing all of Vista's core editions, of which there are six: Windows Vista Starter, Windows Vista Home Basic, Windows Vista Home Premium and Windows Vista Ultimate for consumers and Windows Vista Business and Windows Vista Enterprise for business.

Allchin would not give specific reasons for Vista's delay, but said it is a quality issue and that it was something partners requested. He said they wanted Microsoft to provide them with a clear date for release because it did not seem Microsoft would have the OS ready in time for them to ship it on hardware by late November. That is when the busy Christmas buying season begins, and Microsoft had originally targeted that time for the release of Vista PCs.

"We’re just trying to be responsive to their concerns and also be forthright about where we are in terms of being a few weeks late for quality," Allchin said.

Microsoft said it is not concerned about rival Apple capitalising on Vista's delay because the company thinks customers will still buy Vista simply because of the rich features it will provide.

But at least one analyst suggested Microsoft should be worried, since the delay will have a major effect on Microsoft's entire partner ecosystem.

"They will miss out on the lucrative holiday season and this move will definitely slow down growth in the PC industry," said Sam Bhavnani, a principal analyst with Current Analysis. "The impact is far-reaching and will have a significant impact on computer manufacturers, resellers and ingredient players."

Microsoft is on target to release another Community Technology Preview (CTP) of Vista by the end of June, a completion of the Beta 2 process of the OS, Allchin said. At this point, Vista is already feature-complete and any tweaks made to the OS before its final release will be for quality, he said.

"It’s not new work that we’re adding," Allchin said. "It's simply ... [work in] continuing to make this the most safe and secure system that’s ever been."

Microsoft said that Vista's delay does not affect the release of Internet Explorer 7 for Windows XP in the second half of the year. IE 7 will ship as a feature of Vista, and Microsoft had said the version of IE 7 for XP was to be released at the same time as the OS.