1998
The European Commission investigation into Microsoft's business practices is sparked by a complaint from rival Sun Microsystems, which claimed that Microsoft had failed to provide technical information needed for servers running Sun's Solaris operating system to fully inter-operate with PCs running Windows.
2000
In August, after a year-and-a-half investigation, the EC issues its first statement of objections to Microsoft alleging that Microsoft withheld information that would have allowed "interoperability" of third-party server operating systems with PCs running Windows.
2001
In August, the Commission issues a second statement of objections asserting that Microsoft held a dominant position in the market for workgroup servers and was hindering interoperability between Windows server and third-party server operating systems.
Separately the commission alleges that Microsoft competes unfairly with Real Networks and other vendors of media players by "tying" Windows Media Player with Windows.
2002
Microsoft enters into discussions with European competition officials with a view to settling the EU case.
2003
In August, the Commission issues a third statement of objections that addresses both its interoperability and Windows Media Player allegations. Microsoft requests an oral hearing, which takes place November in Brussels.
2004
On March 24, the Commission issues a decision finding Microsoft in breach of European competition law through the abuse of a dominant market position and fines the company €497m. The Commission's remedy requires Microsoft to create a version of Windows without Windows Media Player and to license Windows Server communications protocols.
In May, Microsoft files an appeal with the European Court of First Instance on the Commission's decision, and in June, specifically asks the Court to suspend implementation of the remedy until after the Court renders a decision. The Court denies Microsoft's request to suspend the implementation of the remedy in the interim.
2005
Microsoft delivers a draft of the licensing program for its Windows Server communications protocols and releases a version of Windows in Europe without multimedia functionality.
In November the Commission alleges that the company had failed to comply with its March 2004 decision on the question of the completeness and accuracy of the technical documentation of the communications protocols. The decision threatens penalties of €2 million a day if Microsoft is not in full compliance with its decision by December 15. Microsoft makes available revised technical documentation amounting to 12,000 pages as well as information on the pricing and categorisation of protocol licences.
On December 22, the Commission issues a fourth statement of objections stating that Microsoft was not in compliance with the decision in regard to technical documentation and that daily penalties would ensue.
2006
Microsoft finalises and agrees on a template for the redevelopment of the technical documentation and a timeline for its delivery. In July, the Commission fines Microsoft €280.5 million for non-compliance with the March 2004 decision and announces that any further finding on non-compliance will result in fines of up to €3 million per day. On November 23, the final revised package of documentation is submitted to the European Commission and Microsoft announces the availability of the documentation to potential licensees.
2007
The Commission issues a fifth statement of objections stating that Microsoft is not in compliance with the March 2004 decision in regard to protocol pricing.
2008
In February, the Commission imposes a record €899m fine on Microsoft for charging "unreasonable" prices to rivals for access to its software.