Why's Microsoft's Windows Boss Leaving? A Bad Job Review?

NEW YORK ( TheStreet) - We know that Steven Sinofsky, product chief for Microsoft ( MSFT) Windows and the Surface line of tablets, is leaving the company. Right after the release of Windows 8, Windows RT and the new tablets. A surprise to many who thought Sinofsky was in the running to be the company's next CEO.

In his resignation statement, Sinofsky said he was "humbled by the professionalism and generosity" of everyone he had "the good fortune to work with at this awesome company".

Microsoft boss Steve Ballmer also had lots of kind words to say about Sinofsky. But, according to a New York Times blog posting, Sinofsky may not have been the Microsoft ultimate "Golden Boy" that all the accolades made him out to be.

The story mentions some of the "problem" items which appeared in Sinofsky's job review last year. The job review reportedly noted his failure to make sure the company lived up to a 2009 agreement with European regulators concerning Windows' built-in Web browser choices. It also blamed Sinofsky for a 3% drop in his Windows division revenues at that time.

In my years working for MSNBC.com, with its newsroom on the Redmond, Wash. "campus" I've been a party to Microsoft-based job reviews. The company uses a scale of 1-to-5, in which 5 means you've been the perfect company employee and a 1 rating meaning you're going to show-up for work one morning (Microsoft employees will recognize this) only to find a newspaper opened to the classifieds draped over your computer keyboard.

I'm guessing that his review might have been in 3.0 range - which, I was told was a good/passing grade. But, for a product manager it sounds like it was more of a warning. Not an outright firing, but not something to brag about. This sort of corporate pressure might have weighed heavily on Sinofsky's mind and ultimate decision.

Windows 8 early teething pains might have also contributed to his decision to leave Microsoft after 23 years. There have already been reports of some hardware problems with Surface tablets and we've found some major software audio problems as well. Not a great start.

We wish Sinofsky good luck in his future endeavors. As for whatever happened in the past it's now up to the new boss, Julie Larson-Green, to see what she can do with a traditionally very profitable division. We wish her good luck.

When contacted by TheStreet, Microsoft said that it had "nothing further to share" on Sinofsky's departure, beyond its press release announcing the news.

--Written by Gary Krakow in New York.

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Gary Krakow is TheStreet's senior technology correspondent.