Microsoft admits to deactivating non-Microsoft security applications in Windows 10

Don't worry! Microsoft has a perfectly valid excuse, honest.

Microsoft has admitted to deactivating third-party anti-virus software in Windows 10. It follows a complaint to anti-trust authorities from security software company Kaspersky.

Last month, Kaspersky founder Eugene Kaspersky wrote a scathing blog, heralding an anti-trust complaint to the European Commission, questioning Microsoft's potential abuse of its place in the market.

It's not the first time anti-trust authorities in the European Union have felt compelled to intervene in Microsoft's business practices. Until 2014, European Windows users were offered a choice of browser during Windows installation, as it was felt that Microsoft had too much power with Internet Explorer.

In an unusually candid blog post, Microsoft's Rob Lefferts explained: "We built Windows Defender Antivirus to make a promise to our customers that every Windows 10 device always has protection from viruses and malware... our test results are among the top of security industry leaders, including recent real-world testing where Windows Defender Antivirus scored over 99 per cent detection rates."

The post goes on to admit that, yes, it does deactivate third party anti-virus software if there is a risk of an update to Windows that stops the AV working anyway.

"To do this, we first temporarily disabled some parts of the AV software when the update began. We did this work in partnership with the AV partner to specify which versions of their software are compatible and where to direct customers after updating," Lefferts said.

A recent example of this is the Creators Update, which has been rolling out to consumers in a much slower fashion than expected and, although compatible with 95 per cent of AV software, there have been some problems. It is in those cases that Windows Defender is primed to take over, claims Microsoft.

As yet it's not clear if this is a satisfactory enough answer for either Kaspersky or the European Commission, as it only seems to partly answer the accusations.

For a start, Microsoft claims that it only "briefly" turns off third-party AV. But the suggestion seems to be that the AV goes off and stays off, with Windows Defender taking over as a result.

If that's genuinely the case, we suspect there'll be a lot more to say on the matter.