A group of Microsoft rivals and customers filed a new complaint with the European Commission today, accusing the US software giant of competing unfairly.
The European Committee for Interoperable Systems (ECIS) said in a statement that Microsoft "threatens to deny enterprises and individual consumers real choice".
ECIS, which dates back to 1989, includes IBM, Oracle, Sun Microsystems, Nokia, RealNetworks and others.
The complaint asks the Commission to put an end to the practices that the group says have hemmed in its members. "ECIS deeply regrets that strong antitrust law enforcement appears to be the only way to stop the sustained anti-competitive behaviour of Microsoft," Simon Awde, chairman of the group, said in a statement.
The group said that limits which were placed on Microsoft in a 2004 antitrust decision - now under appeal by the company - needed to be rapidly and fully enforced.
The group said Microsoft Office software was one example of a Microsoft product that did not permit rivals to interoperate properly with the Windows operating system, preventing them from competing.
"It prevents them from achieving full interoperability," said Thomas Vinje, a lawyer for the group.