European Union (EU) regulators have provided Microsoft with an additional three weeks to respond to complaints about its inability to comply with a 2004 antitrust ruling. The software giant now has until April 23 to respond to the complaint. The previous deadline was set for April 3.

Microsoft, however, had asked for a lengthier deadline extension. "They asked for an extension until the end of May because of the complexity of the question," an EU spokesperson said Monday. In early March, the EU's European Commission (EC) threatened to institute daily fines if Microsoft didn't explain why it was still in noncompliance three years after the ruling. Microsoft has already been fined twice in this case: once in 2004, for $657 million, as part of the original ruling and once in 2006, for $357 million, for its continued failure to comply.

Since that time, Microsoft and the EU have repeatedly disagreed over the quality of server interoperability technical documentation that Microsoft has to supply as the final requirement of its antitrust compliance. Microsoft has submitted the documentation several times but has been rebuked each time by regulators, who have characterized it as "incomplete" and essentially useless.