EU regulators have sent Microsoft a formal complaint, accusing the software firm of failing to give customers a choice among Internet browsers. Microsoft's spat with the EU might cost it 10 percent of its 2012 revenues.
The European Union Executive Commission detailed its charges in a statement of objection, which was sent to Microsoft on Wednesday.
In the statement, EU antitrust regulators said the US software giant had failed to comply with its commitments to offer users a choice screen, enabling them to choose their preferred web browser.
"If companies enter into commitments they must do what they are committed to do. Otherwise they must face the consequences," EU antitrust commissioner Joaquin Almunia told a news conference.
In 2009, Microsoft agreed with EU regulators to offer browser choices in an effort to stop an EU antitrust investigation and to avoid a hefty fine. The EU set a deadline until July this year which was not met by Microsoft.
Microsoft blamed the lapse on a technical error, which had caused the choice screen to vanish from operating systems, especially Windows 7.
Almunia said he had given the company four weeks to respond to the accusations, or face a fine.
Under EU law, a company found to have breached commitments given to resolve such cases may face a fine of up to 10 percent of its annual sales. In the case of Microsoft this could be in the region of $7 billion (5.41 billion euros) in line with 2012 revenues.
uhe/hc (Reuters, dpa)