The European Commission has given Microsoft an additional month to comply with a part of its antitrust ruling that requires Microsoft to provide information allowing competitors' server products to interoperate with its software.

Microsoft now has until February 15 to comply with the ruling before the company is fined up to €2 million a day.

The European Union's antitrust watchdog wants Microsoft to provide documentation allowing its competitors to interoperate with the company's workgroup server systems.

The decision whether to grant the extension was taken by the hearing officer, Karen Williams, a European Commission official not directly involved in the competition investigation.

In December 2005, the Commission formally warned the company that it had failed to comply with the part of its March 2004 ruling on workgroup server interoperability because it supplied inadequate documentation. An independent assessment of the documents submitted to the Commission by Microsoft said any programmer trying to use the documentation for a real development exercise would be "wholly and completely unable to proceed". Trying to use the documentation was an "absolutely frustrating, time-consuming and ultimately fruitless task", according to Professor Neil Barrett, a computer science expert who is examining whether Microsoft is complying with the Commission's ruling.

The extension follows a sharp exchange between the two sides on December 22, when the Commission said Microsoft had failed to comply fully with its March 2004 antitrust decision. Microsoft shot back that it had paid a historic fine and provided unprecedented access to its technology, and also requested an extension.