Microsoft (MSFT) was hit with a $731 million fine on Wednesday for not displaying a required browser choice screen in Windows 7. The European Commission found that nearly 15 million people weren’t given an alternative browser option in Europe from May 2011 through July 2012. According to a report from the Financial Times, the Commission was tipped off about Microsoft’s violation by rivals Google (GOOG) and Opera, both of which would have benefited greatly from the mandatory browser selection screen Microsoft failed to display in Windows.

Microsoft originally claimed that a “technical glitch” was behind the problem and said that it had no plans to appeal the fine.

An Opera spokesperson said the company is “happy to see that the Commission is enforcing compliance with the commitment, which is critical to ensuring a genuine choice among web browsers for consumers.”