Sinofsky OFFSKI: Is Windows 9 now codenamed 'Defenestrate'?
'Inconceivable' - May not mean what you think it means
So Microsoft's Windows 8 chief Steve Sinofsky is offski. Was it corporate politics, modest  Surface RT sales, or some hippie desire to find himself that made him quit?
Whatever the reason, the news of his departure - just three weeks after Microsoft unveiled Windows 8 and said it was its most significant launch since Windows 95 - is nothing less than staggering. And doubly so given Sinofsky was seen as a future Microsoft CEO.
The fact Sinofsky is leaving immediately adds to the intrigue. When the top brass exits any major corporate there's usually an orderly transition period; at Microsoft, even when executives leave under a dark cloud, they don't vacate their desk immediately. Indeed, poor performance is no guarantee of getting the chop at the Redmond giant. There's no suggestion Sinofsky has done anything career-ending, just as there's little evidence of a smooth handover.
Group president of entertainment and devices Robbie Bach, who was responsible for Microsoft's smartphone failure, and Sinofsky's predecessor Jim Allchin - who led the Windows Vista charge - both clung to power while Microsoft closed its ears to calls for change and its mind to the notion that the buck stops with the boss.
If failure is to be measured on a scale of Bach's mishandling of mobile devices and Allchin's Vista debacle, Sinofsky is no failure.
Microsoft CEO Steve Ballmer described sales of the Windows 8-powered Surface RT fondletop  as "modest". Also, there are supply problems leading to shortages in the UK and US; devices are slower than expected and they eat memory; the App Store is stuffed with duplicate programs; and the keyboard is falling apart for some users.
But in terms of just Windows 8, Sinofsky oversaw the development of an operating system with a new user interface, and an ARM port of the Windows NT-derived kernel, allowing Microsoft to stretch into PC hardware - at the risk of upsetting computer makers.
Before Windows, he managed successful releases of Office - including a major and controversial new user interface in Office 2007.
Behind the scenes, Sinofsky also achieved what few could do at Microsoft: he changed the culture. He introduced triads, cells each comprising a developer, a tester and a programme manager to speed up development and tighten coding. The triad model stripped out middle management and was so successful it's been rolled into the Server and Tools division and his old home of Office.
So why go?
Sinofsky calls his choice a "personal and private" one. In a letter to employees , Sinofsky said he always advocated using the break between product cycles as an opportunity to reflect and look ahead. "And that applies to me, too," he added.
It's a fine sentiment, but he must have had a major moment of reflection to leave Microsoft less than three weeks after the launch of the new operating system, and just before the arrival of x86-powered Windows 8 Pro Surface devices. Maybe he had some sort of encouragement.
Some cite Microsoft's viper pit of politics. The software giant is a notoriously Darwinian environment: the fittest thrive, the weak wither into the shadows. Anyone upset by Sinofsky's methods and personality  would want to exploit fissures in his armour, such as the sales of Windows RT and Windows 8 kit and the bruised relationship with PC makers.
These could be enough to weaken him.
But let's suppose instead it was politics of a different kind: perhaps he clashed with Ballmer one too many times, as others have speculated. Is this credible?
Ambitious and nowhere to go
Certainly, Sinofsky is ambitious and will have looked for more power. The question is, where could he go next? Server and Tools has a relatively new executive, and Ballmer's already shaken up phones and gaming with the departure of Bach. The Online division is an option but a poor cousin to Windows, Server and Tools, and Office; it's struggling against Google and it loses money. Why would Sinofsky want to tarnish his image with the risk of a failure?
The suggestion of a clash with Ballmer has some legs: the aftermath of Sinofsky's exit matches the changes inside Bach's former empire, and that of Business Solutions following the exit of that group's president Stephen Elop: responsibilities of the departing chief are distributed among lower executives who have skills in certain areas but who are denied the encompassing role of a group president.
Ballmer has appointed Sinofsky's colleague Julie Larson-Green , who worked with Sinofsky on Office, to lead Windows software and hardware engineering. Tami Reller will retain her role as Windows and Windows Live chief financial officer while taking on the job of running the Windows business.
Whether it was performance, politics or a desire to make a break, it will reflect badly on all concerned. A cloud now hangs over Windows 8, RT and Surface just as Microsoft tries to get a foothold in its uphill climb against Apple.
Sinofsky said he's leaving for personal and private reasons, somewhat countering the notion he's an executive more concerned about his own future rather than the fate of the team he's left behind and the product that's got his fingerprints all over, which was supposed to lead Microsoft blinking into a brand new era.
It will reflect badly on Ballmer for allowing such an individual to slip through his fingers so suddenly - unless it is for a very personal reason, such as health or a family matter, of course.
Worse, it's damaging for development of Windows as big problems remain: we have a Windows 8 operating system on ARM that doesn't work with legacy x86 Windows apps, and a Windows 8 operating system on x86 that won't bring touch to legacy Windows apps. And, aside from any lingering technology problems, Microsoft still hasn't given a satisfactory explanation of how it will explain the differences between a Windows RT and a Windows 8 device to the average punter.
All we've had is an assurance the problems will be solved. That assurance came from Sinofsky before launch, but there were no details.
Also, there's the cultural challenge that must be overcome: getting users ready for the new interface, of having to switch between sessions for Internet Explorer 10 in the classic desktop and Metro, and - yes - that lack of a start button, that those used to running Windows will want to see.
Hovering over all this is Windows 9, because the answer to all these issues is simple: how far does Microsoft go next? Metro all the way, or does it continue to offer a mix of Metro and classic in Window Next?
There are big questions over whether Larson-Green is the right person to lead this work. Read Mini Microsoft , a blog by an anonymous Redmond worker, and it'll become apparent not only just how polarised employees are on the exit of Sinofsky but also the techies' feelings towards his replacement.
Larson-Green is an ex-programme manager and an interface expert; she worked on Metro and was responsible for the introduction of the Office 2007 Ribbon - something that confused users of Office.
Three weeks ago, Microsoft was riding the crest of a wave. "People are walking the hallways tonight at work, and certainly can't believe it. I can't believe it - working at a Microsoft without Sinofsky? Inconceivable," the blogger wrote this week.
Microsoft without Sinofsky isn't inconceivable - it just happened a lot sooner than we expected. There's even a convincing argument that he wasn't indispensable.
What is inconceivable the nature of his departure. It's an exit that's going to damage Microsoft and Ballmer, it will stamp on the growing self-confidence of Microsoft staffers, and it creates great uncertainty over the future of Windows with so many questions left unanswered at a time when it seemed uncertainty was a thing of the past. ®