A shareholder in Microsoft Corp has filed a lawsuit against the software giant over the way it handled an error with its Internet Explorer browser, Reuters reports. The error led to a $731 million fine by European antitrust regulators.

Shareholder Kim Barovic brought the suit in federal court in Seattle on Friday. She alleges that directors and executives, including company founder Bill Gates and former Chief Executive Officer Steve Ballmer, were not managing the company properly and that the board conducted an insufficient investigation into how the incident occurred.