Microsoft has asked the EC for more time to comply with its anti-trust ruling, in particular ensuring full interoperability with workgroup server software.
If the Commission agrees, it will give Microsoft more time to comply with the ruling before the company is fined up to €2 million a day, starting Wednesday.
"Microsoft has requested an extension," said a spokesman for the EU's competition commissioner Neelie Kroes. He declined to comment on the length of the requested delay.
The decision will be 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 inter-operability 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.