Microsoft has lost its bid to suspend sanctions imposed on its business practices by European regulators pending the outcome of an appeal.
The president of the Court of First Instance, the European Union's second-highest court, Bo Vesterdorf has ruled that Microsoft must offer a version of its Windows PC operating system that does not include its Media Player software.
He also ruled that Microsoft must publish application programming interfaces (APIs) that will make it easier for rivals to make workgroup server products that work well with Windows.
The software manufacturer has failed to prove that carrying out the sanctions imposed by the European Commission would cause "serious and irreparable harm" to the company, the court said.
The decision is seen by some as a blow to Microsoft, which had appealed against the Commission's decision issued in March. It means Microsoft will have to comply with the measures pending the outcome of a longer-term challenge to the decision which is expected to take as long as five years.
Microsoft is allowed to appeal Vesterdorf's decision, but the appeal will be difficult to argue and must be based on concerns regarding matters of law, as opposed to facts in the case, according to sources close to the case.
Vesterdorf has taken steps to ward off a successful appeal by preparing a long and detailed judgment, one source close to the case said.
The Commission wrapped up a long investigation into the software manufacturer in March, ruling that it had abused its dominance in the PC operating systems market to gain advantage in related markets, such as that of digital media players, where its competitors include Apple Computer. and RealNetworks.
Along with the behavioral remedies it slapped Microsoft with a fine of €497m (£347m), which the court said the company has paid. The remedies were due to take effect at the end of June, but Microsoft filed a request for the sanctions to be suspended pending the outcome of its appeal.
Simon Taylor writes for IDG News Service
Scarlet Pruitt contributed to this report