Windows Vista won't be released until the end of 2006, a Microsoft exec let slip in a presentation on Microsoft's campus yesterday.

The next version of Windows was expected in the second half of 2006, but at a financial analyst conference in Washington, Microsoft senior VP Will Poole revealed it would not appear until the 2006 US holiday season.

This has been widely interpreted as either the US Thanksgiving holiday, which comes on the last Thursday in November, or Christmas, at the end of December. Poole quickly corrected his faux pas, and reiterated Microsoft's party line that Windows Vista will be ready sometime in the second half of 2006 during the remainder of his presentation.

Microsoft released the first beta of Windows Vista this week, and a demo of some of the new OS has shown some new features, including virtual folders and enhanced support for RSS (Really Simple Syndication).

The company revealed the official name of the client OS, formerly codenamed Longhorn, last week. The next version of Windows Server currently still retains the Longhorn codename, and is expected to be available in 2007.