Microsoft is resisting a plan that would see its Windows Update service being used to aid a class action lawsuit against it.
Lawyers in the "Windows Vista Capable" class-action lawsuit want to use the patching service to encourage other Windows users to join the lawsuit, and have demanded the facility in a federal court, much to Redmond's annoyance.
In response, Microsoft said the move would see Windows Update "hijacked" by lawyers wanting to send out what was in effect "spam".
The Vista Capable lawsuit claims Microsoft duped PC buyers in 2006 and 2007 by allowing PC manufacturers to fix a "Vista Capable" sticker on their PCs, when it knew many of these systems could run only the Vista Home Basic entry-level version of the OS.
The lawsuit claims the Home Basic package is not representative of the Vista OS that Microsoft heavily marketed to consumers.
Microsoft claimed that using Windows Update to send a web link about the case to tens of millions of Windows users - a large chunk of them unrelated to the case - would confuse many of them and cost it dearly in support costs when dealing with concerned recipients of the message.