Mozilla researchers have accused Microsoft of repeatedly using “harmful design” tricks and manipulative “dark patterns” to nudge Windows users towards adopting its Edge web browser, while actively discouraging the use of rivals like Mozilla’s Firefox or Google‘s Chrome.

In a damning 74-page report, Mozilla claims Microsoft has skewed consumer choice and trust in the tech industry through questionable design decisions baked into Windows 10 and 11. Researchers say tactics like visual interference, pre-selecting Edge as default, using misleading wording, and disguising ads as messages have distorted consumer choice and left users unable to easily install or set default alternatives to Edge.

According to the report’s authors – Dr. Harry Brignull, an expert in cognitive science, and Fulbright scholar Cennydd Bowles – there is no justification for making it so difficult to remove Edge from Windows. They argue Microsoft’s experience pushes people towards keeping Edge, from pre-checked boxes to grayed-out, ignorable settings for changing defaults.

The report slams “unsolicited messages” displayed when searching for other browsers, designed to keep users loyal to Edge. Even Microsoft’s Bing search engine can detect and discourage switching browsers. Alongside pop-ups, misleading claims only Edge is secure, and obtrusive surveys, researchers say Microsoft is influencing consumers through problematic design choices alone.

While Microsoft has agreed to let EU users uninstall Edge to comply with antitrust laws, the option remains unavailable for US, UK and other international Windows users. According to researchers, regulators should intervene to halt “harms” from Microsoft’s anti-competitive behavior if the company refuses to make immediate changes voluntarily.

Mozilla has previously raised concerns over an uneven playing field in the browser wars, claiming disadvantages for Firefox against mega-rivals like Chrome, Safari and Edge. But this new report directly accuses Microsoft of manipulating Windows users against competitors through ingrained design decisions. With Chrome holding 64% of the market share worldwide, Safari 19%, Edge 5% and Firefox just 3%, Mozilla argues Microsoft’s tactics are severely limiting consumer choice.

Source: StatCounter Global Stats – Browser Market Share