A Microsoft executive familiar with the senior management stressed that there wasn't a single event that led to Sinofsky's departure after the launch of Windows 8. Instead, it's said that the relationship between Ballmer and Sinofsky deteriorated as the development on the firm's latest operating system progressed.
Sources suggest the two executives came to a number of disagreements in the past months. Although Ballmer wanted Sinofsky to exit the software giant, Microsoft stressed that the decision was mutual.
Apparently, the biggest reason for Ballmer letting go of Sinofsky is his concern of the former employee not working well with fellow executives from other groups.
"Ballmer is on this big kick to get different pieces of the company working together and Sinofsky had his middle finger extended," said a former Microsoft executive.
Sources familiar with discussions to the naming of Sinofsky to manage the Windows division stated that it was an area of "concern" for both Ballmer and Chairman/co-founder Bill Gates. "Bill and Steve both knew Steven's flaws," said one former senior leader. However, the pair were willing to dismiss their worries as he fixed the problems within the Windows group after the launch of Windows Vista.
According to one former senior executive, Sinofsky had threatened to quit his position more than once due to strategic decisions not going his way. "They bet on Steven and they kept betting bigger and bigger," the ex-employee claimed.
Top Microsoft executives who clashed with Sinofsky and then lost left the firm such as the likes of former Chief Software Architect Ray Ozzie and former Server and Tools Division President Bob Muglia.
Ballmer's memo regarding Sinofsky's departure saw the CEO stating that in order for Microsoft to continue to be successful, "it is imperative that we continue to drive alignment across all Microsoft teams, and have more integrated and rapid development cycles for our offerings." Steven Sinofsky also sent his own memo to all Microsoft employees.