The European Union's General Court today rejected Microsoft's appeal of a 2008 antitrust ruling in which the software giant was fined €899 million ($1.12 billion) for failing to comply with a previous antitrust decision.

The case goes all the way back to 1993 when Novell complained about Microsoft licensing practices. The circumstances relevant to today's ruling occurred between 1998 and 2004: during that time, Microsoft was found to have refused to give its competitors interoperability information, preventing competitors' products from being able to work with Microsoft's Windows server software. In 2004, the European Commission "required Microsoft to grant access to that information and to allow the use of it on reasonable and non-discriminatory terms," the EU's General Court noted today.

But Europe and Microsoft disagreed over how to define fair rates, and Microsoft "failed to provide a complete and accurate version of the interoperability information," leading to several fines, the biggest one being a 2008 penalty of €899 million. Microsoft appealed the 2008 ruling, saying the Commission's ruling wasn't clear enough and that the Commission erred in "requiring Microsoft to establish that its trade secrets were innovative" in order to justify the charging of royalties for its trade secrets.

Today's ruling (full text) upheld the fine and rejected all of the arguments put forward by Microsoft. "Microsoft has failed to invalidate the Commission’s assessment that 166 of the 173 technologies relating to the interoperability information were not innovative," the court said.

Microsoft got one piece of good news from today's ruling. The Court lowered the fine 4.5 percent to €860 million ($1.07 billion) because of a letter the Commission sent to Microsoft on June 1, 2005. In that letter "the Commission accepted that Microsoft could restrict distribution of products developed by its ‘open source’ competitors on the basis of non-patented and non-inventive interoperability information until delivery of the Court’s judgment," or until Sept. 17, 2007. But the letter was relevant only to a marginal part of the case and did not affect the ruling as a whole.

Microsoft has a long history of tangling with antitrust regulators in the US as well regarding the methods it used to maintain monopolies in the operating system and Web browser markets. Today's ruling is a reminder that Microsoft is still paying a price for its actions in its bad old days. Microsoft has not said whether it will appeal the decision to Europe's highest court, but in a statement quoted by Reuters said "Although the General Court slightly reduced the fine, we are disappointed with the court's ruling."