Microsoft may have shipped Zune in time for Christmas – but it hasn't yet managed to make sure its MP3 player will be supported by its forthcoming OS (operating system), Windows Vista.

Users trying to install Zune software on the latest versions of Vista are told the OS isn't supported by the player. This is confirmed by an official support document, AppleInsider reveals.

Microsoft will begin selling Vista to business customers in two weeks. A Microsoft spokesperson told PC Advisor that "Zune will support all versions of Vista - when they become available". He went on to highlight the fact that statements to this effect were already available in the FAQs pages of Microsoft's site.

Microsoft is extremely keen to prevent pirated versions of the new Windows Vista operating system and, with cracked versions of the soon-to-be-launched OS doing the rounds, it makes sense not to cite compatibility with an unreleased product.

Zune also offers no support for so-called 'Plays For Sure' music acquired from Windows Media Player-backed services, such as Napster.

Early reports on the Zune have been largely favourable.