Microsoft today announced the immediate departure of Windows executive Steven Sinofsky. Julie Larson-Green, who has worked at the company since 1993, will now take the reins of Windows software and hardware engineering, while CFO Tami Reller will now be in charge of Windows business.

Microsoft didn’t release a reason for Sinofsky’s sudden departure, which comes less than a month after the launch of Windows 8, Sinofsky’s most recent project. In a letter to Microsoft emplotyess, CEO Steve Ballmer wrote:

As we enter this new era, and with the successful launch of Windows 8 and Surface behind us, Steven Sinofsky has decided to leave the company. Steven joined Microsoft in 1989 as a software development engineer and has contributed to the company in many ways from his work as a technical advisor to Bill Gates, to leading the evolution of the Microsoft Office business, to his direction and successful leadership of Windows and Windows Live as well as Surface.

Hours after the annoucment was made, The Verge heard from sources inside the Redmond-based company that Sinofsky’s departure wasn’t because of issues with Windows 8 or the Surface tablet, but rather a clash of personalities within the company’s headquarters.

It’s possible that his departure was pre meditated and Microsoft chose the keep Sinofsky on the team till the Windows 8 launch was over.

Whatever the real reason why Sinofsky left the company, Microsoft is clearly losing a quite important member of their team. And the fact that his departure was so sudden, there may be more behind it.

How do you think Windows will be without Sinofsky?