Read moreMicrosoft is preparing to detail its next major version of Windows. We had been expecting the company to hold a press event later this month, and now it’s official. Microsoft will hold a "Windows event" in San Francisco on September 30th. The software maker started emailing out invites to the event today, and Joe Belfiore and Terry Myerson will be leading a discussion around the future of Windows. The event will focus on enterprise and power users of Windows.