The EU Commission has fined Microsoft €280.5m for anti-competitive business practices.
Microsoft failed to comply with a 2004 ruling ordering it to share server APIs and offer Windows without Media Player bundled along with it.
European Competition Commissioner Neelie Kroes said: "I regret that, more than two years after the decision and despite an order from the president of the Court of First Instance that the Microsoft appeal to the Court does not suspend Microsoft's obligation to comply, Microsoft has still not put an end to its illegal conduct."
Microsoft general counsel Brad Smith said: "We have great respect for the commission and this process, but we do not believe any fine, let alone a fine of this magnitude, is appropriate given the lack of clarity in the commission's original decision and our good-faith efforts over the past two years.
"It is hard to understand why the commission is imposing this enormous fine when the process is finally working well and the agreed-upon finish line is just days away. The fine announced today is larger than the fines the commission has imposed for even the most severe competition law infringements, such as price-fixing cartels."
If Microsoft continues to refuse to supply "complete and accurate" information to other developers by 31 July, the commission said it would start fining it an additional €3m a day.
A statement said: "Microsoft's obligations in this regard are clearly outlined in that decision, both in terms of the result to be achieved, and in terms of what Microsoft must do to achieve that result. These obligations were specific and have not changed: it is for Microsoft to produce usable documentation."
See the commission statement here.
Microsoft has repeatedly insisted it has fully complied with the 2004 ruling. The Luxembourg court which heard its appeal against Brussels in April has yet to rule.®