The launch of Windows Vista appears to have slipped towards the back end of this year, according to Microsoft Watch, a Web site that tracks the software giant closely.

Microsoft Watch reported on Tuesday that an official blog for Microsoft's business developers had revealed that the launch of Vista would take place in November 2006.

Previous reports had suggested that Vista might hit the shops in October, although there have also been unconfirmed claims that the launch date will be 15 November.

"This is the year... the year that Microsoft releases the newest version of Windows. Yes, Vista will be released in November of this year," wrote Microsoft's Greg Randall, according to Mary Jo Foley of Microsoft Watch.

However, within hours, the post had been edited to read "We are targeting to make Windows Vista generally available in the second half of this year."

Vista will be one of Microsoft's most important product launches for years. There will be six different versions.

Microsoft is also planning a massive advertising blitz to push Vista. Despite this, there are doubts that Microsoft will be able to quickly shift large numbers of customers from its earlier operating systems onto Vista.

Late last year, analysts at Gartner suggested that many companies could hold back from migrating to Vista until 2008. It later added that it would be wise to start planning a migration once Vista shipped.

ZDNet UK's Graeme Wearden reported from London. For more coverage from ZDNet UK, click here.