 In 2004 the European Commission found Microsoft guilty of anti-competitive behaviour with respect to interoperability in the workgroup software market.Microsoft had formerly settled "United States v. Microsoft" in 2001, in a case which charged that it illegally abused its monopoly power to force computer manufacturers to preinstall Internet Explorer.The Commission demanded that Microsoft produce full documentation of its workgroup protocols to allow competitors to interoperate with its workgroup software, and imposed fines of 1.5 million euros per day for Microsoft's failure to comply.