Microsoft has filed an appeal against a €280.5m fine imposed by the European Commission for failing to obey an earlier competition ruling.

The European Court of First Instance in Luxembourg confirmed it had received a faxed copy of the appeal from Microsoft and was waiting for the original to arrive.

Microsoft said the 'unprecedented' fine was unfair and the EU had not been clear about its demands and how it should present the information. The US software giant had announced its intention to appeal after the fine was imposed in July.

The commission imposed the fine to punish Microsoft's failure to comply with a landmark 2004 competition ruling. It came on top of a record €497m fine the slapped on Microsoft in March 2004 for abusing its dominant position.