Mozilla Accuses Microsoft: Firefox Threatened by Windows and Copilot

Mozilla Accuses Microsoft of Threatening the Existence of Firefox

Mozilla has recently voiced its concerns regarding Microsoft's practices, accusing the tech giant of harming Firefox. In a blog post published on April 9, Mozilla claims that Microsoft is sabotaging its browser through the Windows ecosystem. While criticisms of Microsoft are not new, Mozilla is expanding its accusations this time to include not only the Edge browser but also other services like Copilot.

Microsoft's Practices Under Scrutiny

Mozilla details how, despite the selection of a default browser in Windows, several applications and services continue to open links in Edge. For instance, searches conducted from the Windows taskbar consistently redirect to Edge, ignoring user preferences. Additionally, applications like Outlook and Teams follow the same logic.

The arrival of Copilot in March 2026 has intensified the issue. This Microsoft AI assistant integrates links into a sidebar using the Edge engine, without offering an option to disable this feature. Mozilla emphasizes that this practice goes against the guidelines of the European Digital Markets Act (DMA), which aims to ensure fair competition. In contrast, Mozilla highlights that its own AI tools in Firefox are entirely optional and can be easily disabled.

Firefox Facing an Economic Crisis

Beyond software philosophy issues, Mozilla is facing an economic crisis. Firefox now accounts for only 2.2% of the global market share across all platforms, according to StatCounter. On desktop computers, this figure ranges between 4% and 6%, with a notable exception in France where it reaches around 12%. Meanwhile, Edge has surpassed 9%, while Chrome dominates with over 70%.

Mozilla does not have the same resources as its competitors, as it does not sell operating systems, cloud services, or office suites. Its revenue primarily depends on partnerships with search engines like Google, based on the volume of queries made through Firefox. Each link intercepted by Edge or Copilot reduces this volume, thereby weakening Mozilla's position during the renegotiation of these agreements.

A Call for Technological Diversity

Mozilla's complaint goes beyond merely defending user choice. It highlights the economic fragility of Firefox, the last major independent browser in the Chromium ecosystem. While Chrome, Edge, Opera, and Brave all rely on the same engine, Gecko, used by Firefox remains the only large-scale technical alternative. Safari, on the other hand, is limited to the macOS ecosystem. The survival of Firefox is therefore essential to maintain technological diversity in the browser landscape.