European Union regulators have just slapped Microsoft with a hefty $732 million fine after it failed to live up to its promise to give millions of Windows users a choice of which internet browser to use upon installing the software for the first time.

Microsoft had voluntarily agreed to give European consumers a choice of browser in order to head off allegations of anti-competitive behavior. Previously, the Redmond-based firm had effectively been ‘forcing’ new customers to use its Internet Explorer browser by default, without making it known that there are alternatives available. While most technically-minded consumers know all about the different browser options such as Google Chrome, Firefox and Opera, there are clearly many people who don’t, meaning that IE gains a massive advantage through being set as the default option.

Back in 2009, Microsoft agreed to stop pushing European customers to IE and instead display a choice of leading browsers following the initial Windows setup, something that it did for two years. However, due to what Microsoft called a “technical error”, this ‘browser-choice’ page disappeared for about 18 months from February 2011 to June 2012, which meant that an estimated 15 million customers were never given the chance to switch from IE to something else.

The fine is just the latest in a never-ending run of legal tangles between Microsoft and the EU, which has seen the Redmond company hit with fines totaling some $2 billion for previous anti-competitive practices, such as tying its media player to Windows and failing to provide its rivals with information at fair prices. That the EU has slapped it with an additional $732 penalty might seem pretty harsh, but EU competition commissioner Joaquin Almunia had already indicated he wouldn’t go lightly on Microsoft when he said he wanted to make an example of it to dissuade others from breaking promises in future:

“Legally binding commitments reached in antitrust decisions play a very important role in our enforcement policy because they allow for rapid solutions to competition problems. Of course, such decisions require strict compliance. A failure to comply is a very serious infringement that must be sanctioned accordingly,” he said at the time Micrsoft’s non-compliance was revealed.

Microsoft is yet to comment on its latest punishment, but it would be a surprise if the firm made any effort to challenge the fine seeing as it has already owned up to the mistake.