On a warm night in late October, Steven Sinofsky stood on a platform in New York's Times Square, smiling as a huge crowd roared at the unveiling of a Microsoft retail store, where Windows 8 and the company's new Surface tablet were about to go on sale.
Less than three weeks later, Mr. Sinofsky -- who, as the head of Windows, was arguably the second-most important leader at Microsoft -- suddenly left the company. His abrasive style was a source of discord within Microsoft, and he and Steven A. Ballmer, Microsoft's chief executive, agreed that it was time for him to leave, according to a person briefed on the situation who was not authorized to speak publicly about it.
Mr. Sinofsky was widely admired for his effectiveness in running one of the biggest and most important software development organizations on the planet. But his departure, which Microsoft announced late on Monday, parallels in many respects that of Scott Forstall, the headstrong former head of Apple's mobile software development, who was fired by Apple's chief executive, Timothy D. Cook, in late October.
Both cases underscore a quandary that chief executives sometimes face: when do the costs of keeping brilliant leaders who cannot seem to get along with others outweigh the benefits?
The tipping point that led to Mr. Sinofsky's departure came after an accumulation of run-ins with Mr. Ballmer and other company leaders, rather than a single incident, according to interviews with several current and former Microsoft executives who declined to be named discussing internal matters.
One example of the kind of behavior that hurt Mr. Sinofsky's standing at the company occurred this year at a two-day retreat for Microsoft's senior executives at the Semiahmoo resort on the coast just below the Canadian border in Washington State. At the meeting, Microsoft's various division heads were expected to make presentations on their businesses, answer questions and remain to hear their peers repeat the exercise.
When Mr. Sinofsky stood on the first day to speak about the Windows division, he told the group he had not prepared a presentation, and if they wanted to catch up on the progress of Windows 8, they could read his company blog, where he publicly chronicled the software's development. He answered questions from the audience and then left the resort, while his colleagues remained until the next day, according to multiple people who were present.
Mr. Sinofsky's early exit and halfhearted presentation were widely noted by his colleagues, irking even his admirers in the company. "He lost a lot of support," one attendee said.
It wasn't until this Monday, though, that Mr. Sinofsky and Mr. Ballmer both decided it would be best if Mr. Sinofsky left. Bill Gates, Microsoft's chairman, supported the move, a person briefed on the matter said. Mr. Sinofsky served as a technical assistant to Mr. Gates in the 1990s.
In an e-mail to Microsoft employees, Mr. Sinofsky said the decision to leave "was a personal and private choice." Many surprised Microsoft insiders noted that Mr. Sinofsky's departure was immediate, an unusual arrangement for someone with a 23-year track record at the company. A Microsoft spokesman, Frank Shaw, said Mr. Sinofsky was not available to comment.
Although Mr. Ballmer grew increasingly impatient with Mr. Sinofsky throughout the year, he held back from taking any action earlier to avoid disrupting the release of Windows 8, the most important product Microsoft has unveiled in years, a person with knowledge of his thinking said.
The final decision could not have come lightly. Although many people at Microsoft viewed him as a ruthless corporate schemer, Mr. Sinofsky ran the highly complex organization responsible for Windows as a disciplined army that met deadlines, and he was respected by people on his team.
He achieved hero status within Microsoft several years ago by taking over the leadership of Windows after the debacle that was Windows Vista, a much-delayed operating system whose sluggish performance and technical problems worsened Microsoft's reputation for mediocre software. Mr. Sinfosky led the development of a new version of the operating system, Windows 7, which was positively reviewed and sold well.
"He did great things with Windows," said Michael Cusumano, a professor at the Sloan School of Management at the Massachusetts Institute of Technology. "That's still the core of the company."
But while Mr. Sinofsky was effective, Mr. Cusumano said, he could be secretive and difficult to get along with, as he learned while dealing with Mr. Sinofsky while Mr. Cusumano was writing a book on Microsoft in the early 1990s. "I could imagine that he burned a lot of bridges and created a bunch of enemies," he said.
Mr. Sinofsky's bridge to Mr. Ballmer began to weaken over time. Mr. Ballmer and other Microsoft executives were incensed by the failure of Mr. Sinofsky this year to take ownership of the company's failure to comply with an agreement with European regulators on Web browsers, which could result in a substantial fine. (Microsoft had committed to including a screen in its operating system that let new users easily install competing browsers.)
Mr. Ballmer was also frustrated by the relatively sparse selection of applications available for Windows 8. Mr. Ballmer has long been an advocate of the importance of independent developers in making Windows successful.
Mr. Sinofsky's success with Windows led to constant speculation that he was the heir apparent to Mr. Ballmer, whose own tenure as chief executive has been marked by missteps. Mr. Sinofsky, an engineer, had the technical expertise that Mr. Ballmer, with a background in sales, lacked.
But Mr. Ballmer has revealed no plans to leave Microsoft. Even if he had, Mr. Sinofsky's detractors had predicted a mutiny within the company if he were given the top job. Moreover, people who know Mr. Sinofsky do not think he was interested.
"It didn't strike me that it was his life's ambition," said Marco Iansiti, a professor at the Harvard Business School who wrote a management book with Mr. Sinofsky. "I don't know if he had any real aspirations to run the whole thing."
Like Mr. Sinofsky, Mr. Forstall, the former Apple executive, was sometimes described as a potential successor to Mr. Cook as chief executive. Mr. Forstall also has a technical background and was a disciple of Steven P. Jobs, Apple's late chief.
Mr. Forstall accomplished great things as the leader of the teams behind the software for Apple's iPhone and iPad. But he was also so disliked by other members of Apple's senior management that they could not stand to be in meetings with him, according to people who are knowledgeable about Apple's inner workings.
One concern in getting rid of forceful executives like Mr. Forstall and Mr. Sinofsky is that their employers will begin developing products by committee, rather than in the sometimes heated crucible of clashing personalities, where someone with the strongest vision can prevail.
But one Microsoft executive said Mr. Sinofsky's departure was not a choice of harmony at the expense of creative tension.
"You need both," this person said.
This article originally appeared in The New York Times.