Microsoft pushed back the consumer version of Vista until January 2007 from an earlier target for the second half of 2006 and pledged to ship the next version of its operating system to business customers in November."It is a critical eight- to 10-weeks for retailing and for the producers. The retailers and PC hardware manufacturers work on razor-thin margins, so the impact there could be pretty severe," said David Smith, analyst at Gartner.
The explanation for the delay is that Microsoft wants to improve overall quality, particularly in security, and that PC makers didn't want the operating system introduced in the middle of holiday sales, because a new version would create instability in the market.
It's not the first time Microsoft delays the launch of Vista (previously codenamed Longhorn), 2005 was another deadline.
New York Times: Microsoft to Delay New System