The man who presided over Microsoft’s Windows division during the launch of Windows 8 left the company unexpectedly this morning, “effective immediately”.

Considering the recent launch of Windows 8, and the critical praise the Surface has received, Steven Sinofsky’s departure may come as a surprise to many. However, to Microsoft watchers, this departure was expected as tensions between Mr. Sinofsky and Microsoft Master Chief Steve Ballmer were high.

Despite reports of tensions between Sinofsky and Ballmer, both men had cordial public words for each other in departure.

“I am grateful for the many years of work that Steven [Sinofsky] has contributed to the company,” CEO Steve Ballmer said in a release. “The products and services we have delivered to the market in the past few months mark the launch of a new era at Microsoft.

“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,” Mr. Ballmer added.

“It is impossible to count the blessings I have received over my years at Microsoft,” Mr. Sinofsky said in his own statement. “I am humbled by the professionalism and generosity of everyone I have had the good fortune to work with at this awesome company.”

To many, Sinofsky’s legacy will not be Windows 8 but the turnaround of the Windows division after the largely panned launch of Windows Vista.

Microsoft announced that Windows division lieutenant Julie Larson-Green has been promoted to Mr. Sinofsky’s old position. Ms. Larson-Green was previously the Corporate Vice President, Program Management, Windows Client. This position had her responsible for all of Windows’ future planning.

As a source that spoke to Fast Company on the condition of anonymity noted, Ms. Larson-Green is representative of the ‘old-guard’ (and perhaps a Ballmer loyalist) of Microsoft.

“I don’t think that Microsoft has changed genetically that much because the type of people in leadership positions haven’t changed all that much. It’s the same people. Julie has been around for two decades,” Fast Company’s source noted.

Some technology analysts believe that Sinofsky’s departure wasn’t as cordial as the public releases make it out to be.

“‘Effective immediately’. Two words that always indicate an ugly executive departure,” Patrick Moorhead of Moor Insights & Strategy tweeted. “Or personal reasons.”

Tags: Microsoft, Steven Sinofsky, windows