FILE - In this Thursday, Aug. 23, 2012 file photo, the Microsoft Corp. logo, left, is seen on an exterior wall of a new Microsoft store inside the Prudential Center mall, in Boston. Microsoft will use its annual developers conference to release a preview of Windows 8.1, a free update that promises to address some of the gripes people have with the latest version of the company's flagship operating system. The Build conference, which starts Wednesday, June 26, 2013, in San Francisco, will give Microsoft's partners and other technology developers a chance to try out the new system before it becomes available to the general public later in the year. (AP Photo/Steven Senne, File)