A Microsoft spokesperson said it made sure the validation tool used by its Windows Genuine Advantage (WGA) programme identified Wine users, so that only users are running a genuine version of Windows could download updates and add-on tools.
"As the most popular third-party translation technology in use, Wine was the first emulator to be specifically tested for via WGA," said the spokesperson. "Microsoft does not knowingly provide copyrighted Microsoft Windows OS files to users of third-party emulators or cross-platform API translation technologies such as Wine."
The spokesperson said users who are not running Windows XP or Windows 2000 natively can still download updates for Microsoft Office from the Office Update Web site.
Microsoft's public acknowledgement of Wine suggests a shift in corporate policy. Earlier this week Jeremy White, chief executive at CodeWeavers, which sells products based on Wine, said that Microsoft has until now had "a clear corporate policy to not talk about Wine".
For this reason, White said he was excited rather than worried to hear that the WGA validation tool was blocking Wine. "The reason we love this is because this shows that Microsoft is aware of Wine at very high levels," said White. "For us it's exciting -- it is an acknowledgement of us as a threat."
ZDNet UK's Ingrid Marson reported from London. For more coverage from ZDNet UK, click here.
If the target of the WGA tests built into Windows Update are specifically to exclude WINE, then 99.99% of the user base will run the code. WINE would be happy because library updates would probably break it. This move helps the stability of WINE at the expense of billions of CPU cycles around the planet.