Microsoft faces further fines in the European Commission's antitrust case for allegedly setting unreasonable prices for software rivals seeking interoperability information.
The latest formal charges could lead to new fines against the U.S. software giant, the Commission said in a statement Thursday.
The Commission found in 2004 that Microsoft violated European Union antitrust rules by failing to give to other makers of small-business servers the information they needed to compete with some of Microsoft's own products.
Microsoft has said it would charge for interoperability information because it was based on its own innovative work.
Microsoft has four weeks to reply to the charges.
The Commission rejected 1,500 pages of information provided by Microsoft. It is still reviewing whether information submitted earlier to help software makers develop programs that run smoothly with Microsoft's Windows operating system is complete and accurate.
Microsoft has appealed the original 2004 decision to a European court, which is due to decide on the case this year.