Kaspersky Lab has filed antitrust complaints in Europe against Microsoft. Kaspersky first filed a complaint against Microsoft with Russia’s Federal Antimonopoly Service (FAS), claiming that Microsoft is using its dominant position with Windows to push its own anti-virus software over competitor products with Windows 10. While Microsoft has made some product changes since the initial complaint, Kaspersky isn’t happy these are enough and has filed complaints with the European Commission and the German Federal Cartel Office recently.

“Microsoft uses its dominant position in the computer operating system (OS) market to fiercely promote its own – inferior – security software (Windows Defender) at the expense of users’ previously self-chosen security solution,” says Eugene Kaspersky, the Russian co-founder of the anti-virus company. Kaspersky claims Microsoft has been removing its software when users upgrade to Windows 10, and enabling its own Windows Defender solution. Kaspersky also claims Microsoft does not provide enough time to fully test its latest Windows 10 upgrades to ensure existing software is compatible.

Microsoft's Windows Defender is built into Windows 10

Microsoft has been gradually improving its Windows Defender anti-virus software in recent years, and with Windows 10 the company has built it into the operating system and enabled it by default. While Microsoft argues this is to protect Windows users, anti-virus makers like Kaspersky argue it's anti-competitive. “We want Microsoft to stop misleading and misinforming our – and not only our – users,” says Kaspersky in a blog post. “We want to see all security solutions being able to work on the Windows platform on a level playing field.”

Microsoft believes Windows 10 complies with competition laws. “Microsoft’s primary objective is to keep customers protected," says a Microsoft spokesperson in a statement to The Verge. "We are confident that the security features of Windows 10 comply with competition laws. And we will answer any questions regulators may have.”

Microsoft also says it has offered to meet with Kaspersky officials to work through their complaints. "We’re always interested in feedback from other companies and we engage deeply with antimalware vendors and have taken a number of steps to address their feedback," says a Microsoft spokesperson. "We reached out directly to Kaspersky a number of months ago offering to meet directly at an executive level to better understand their concerns, but that meeting has not yet taken place.”

Update, 12:30PM ET: Article updated with an additional Microsoft statement.