Steven Sinofsky, Microsoft's Windows President, Leaves Company

Here's a twist nobody saw coming: Steven Sinofsky, the President of Windows and lead architect on Windows 8 has announced his resignation from the company. That's an abrupt change considering that Sinofsky had been floated as a possible replacement for Ballmer in certain circles and his helming of Windows 8 was seen as a project that could reinvent Microsoft.

"I am grateful for the many years of work that Steven has contributed to the company,” Ballmer said. “The products and services we have delivered to the market in the past few months mark the launch of a new era at Microsoft. We’ve built an incredible foundation with new releases of Microsoft Office, Windows 8, Windows Phone 8, Microsoft Surface, Windows Server 2012 and ‘Halo 4,’ and great integration of services such as Bing, Skype and Xbox across all our products. To continue this success it is imperative that we continue to drive alignment across all Microsoft teams, and have more integrated and rapid development cycles for our offerings."

Sinofsky, for his part, said: "It is impossible to count the blessings I have received over my years at Microsoft. I am humbled by the professionalism and generosity of everyone I have had the good fortune to work with at this awesome company."

Microsoft's Julie Larson-Green
Julie Larson-Green - Windows Heir Apparent

Sinofsky's role will henceforth be split by Julie Larson-Green and Tami Reller. Larson-Green will assume responsibility for Windows hardware and software engineering, while Reller takes charge of the Windows business. Both women are seasoned executives within the company and eminently capable of handling the new positions. Taking over from Sinofsky shouldn't be a problem, but that leaves the question of why the Windows 8 head has left in the first place.

According to some reports, Ballmer and Sinofsky fought on a number of issues; Sinofsky was rumored to be ruthless when it came to fighting for control over every product that interfaced with the Windows operating system. Sinofsky took over the Windows group in the wake of Vista's disastrous debut, but his method of running the organization reportedly angered a number of prominent executives.

In this case, it's clear that someone high up the Windows food chain had a problem with the erstwhile manager and had him dismissed. Claims that the departure was mutual simply don't track; Sinofsky has been the visible face of Windows 8 throughout the operating system's development. Even if he'd initially planned to leave after the job was done, MS would've prioritized working with him on a gradual roadmap, not an unexpected departure announcement.

Whether Sinofsky's departure has anything to do with the uptake on Windows Surface or Windows 8 isn't something we know yet, but Ballmer made headlines earlier today by noting that Windows Surface sales had been "modest" (a statement Microsoft scrambled to say has been taken out of context).