Steven Sinofsky, the head of Windows and the guy who presided over the launch of both Windows 8 and the Surface, has officially left Microsoft effective immediately. According to a Microsoft press release announcing the leadership shakeup, Julie Larson-Green will be promoted to head of all Windows software and hardware engineering, while CFO and CMO Tami Reller takes on the business of Windows.

AllThingsD reports that there has been growing tension between Sinofsky and other executives at Microsoft, and the two decided to part ways mutually. Sinfosky has been at Microsoft since 1989, working mostly in the Office unit before his promotion to President of the Windows Division in 2009. His duties as President included work on Internet Explorer,, SkyDrive and other (former) Live services, as well as restoring the Windows division after Vista’s less than desirable launch.