"We are close to our decision. It could be one of the first anti-trust decisions in 2013," EU Competition Commissioner Joaquin Almunia said.
"Microsoft recognises that they were not implementing properly the binding commitments" it made in 2011-12 when it introduced its Windows 7 system, Almunia noted.
Microsoft apologised for what it said was a "technical error" on Windows 7 as the EU launched a probe in July into why 28 million users were unable to choose between the company's default Internet Explorer and other browsers.
The Commission charges the company with failing to offer a browser choice on Windows 7 between February 2011 and July 2012, when the company has said it remedied the problem.
Under EU law, a company found to have breached commitments made to resolve competition cases can face a fine of up to 10 percent of annual sales.
The EU fined Microsoft 899 million euros in 2008, subsequently reduced to 860 million euros, for failing to comply with an order to share product information with rivals so that their software could work with Windows.