The hearing, taking place on Thursday and Friday, gives Microsoft an opportunity to argue why it believes it has complied with the ruling.
A Commission representative told ZDNet UK that a decision on whetherof up to $2.43 million daily, will not be made for "at least several weeks after the hearing." He was unable to comment on the content of the hearing itself.
Microsoft was due to hold a press conference on Thursday to discuss the hearing, but was asked to cancel the conference by the Commission. "This morning, the Commission's hearing officer made a clear request to all parties in the Microsoft oral hearing to respect the confidentiality of the process. Microsoft will respect this request and has therefore cancelled the press briefing," Microsoft said in a statement.
The Commission's representative said he did not know exactly what the hearing officer said, but pointed out that the hearing is meant to be private.
"It would be a little bit contradictory to organize a press conference about a hearing that is private," he said.
But one source who was present at the hearing noted: "It's clear there's no change in the position of the Commission."
Microsoft spent the day presenting its evidence, which included addressing allegations it has not provided adequate interoperability information to its competitors, as well as discussing technical questions relating to its software.
The last portion of the hearing was devoted to questions from the Commission's examination team and hearing officer.
The questions ran along the lines of recapping statements Microsoft had previously made and asking the software giant to elaborate on the meaning of those comments.
On several occasions during the question and answer session, Microsoft reiterated how it wanted the Commission to state in writing what it needed to do to comply with the order, and that it did not fully understand what the Commission was specifically seeking.
The Commission, however, was not sympathetic during the hearing, telling Microsoft, "Look, you were fully aware of our decision," according to the source.
Although the Commission appears unwavering in its decision that Microsoft has not complied with the order, the prospect for reaching a settlement on the fine may be greater, the source said.
During the hearing, one member of the Commission's examination team noted that Microsoft has "made some progress" in providing better documentation.
"Because there has been continuous improvements in documentation, a settlement may be possible, whereas before the Commission refused to settle," the source speculated.
Microsoft tried to strengthen its case for compliance on Thursday by presenting the Commission with statements from six technology companies that claim they have found previous versions of Microsoft technical documentation useful. The six companies, which include storage companies EMC and Network Appliance, are licensees of the Microsoft Communications Protocol program and have used this to develop commercial products. Microsoft says this program offers technical documentation that is "similar" to that which it is offering in response to the antitrust ruling, via its Windows Server Protocol program.
But the Commission was unimpressed with Microsoft's latest attempt to prove compliance.
"Irrespective of these six companies who have done some type of deal with Microsoft in the U.S., the Commission is still of the opinion that the information provided by Microsoft is not satisfactory. Lots of companies tell us it's not satisfactory, and the trustee who was suggested by Microsoft and is a leading computer expert, has concluded that the documentation was totally useless," said the Commission representative.
This is only the latest attempt by Microsoft to try to convince the Commission that it is working hard to comply. Last week, Microsoft offered to provide free, unlimited technical support to companies that license its protocols, but the Commission responded that such support is only helpful once the documentation has reached a certain level of quality.
Third parties that have an interest in the case will go before the Commission on Friday to present their documents and testify.
One group that will be presenting, trade organization CompTIA, issued a statement Thursday saying that it was disappointed the private hearing was not open to the public.
"In order to function within the EU regulatory framework, the information and communications technology industry needs to have access to the regulatory decision-making process, so that it may know where it stands on the design and delivery of its consumer-oriented products and services," Hugo Lueders, a CompTIA spokesman, said in a statement.
Ingrid Marson of ZDNet UK reported from London. CNET News.com's Dawn Kawamoto contributed to this report from San Francisco.