Microsoft ended software support for Windows 10 in October 2025, bringing an end to the operating system launched in 2015. Although Windows 10 PCs will and do continue to function today, they are inherently more susceptible to bugs, glitches and online hacks as they no longer receive important monthly security fixes.

That’s one thing, but as spotted by Techradar Pro, Microsoft is rolling out an important, separate security update to Windows PCs, and it means Windows 10 users could be put at even further risk with outdated software.

Microsoft confirmed it is rolling out new Secure Boot certificates, as the previous certificates are about to expire after 15 years. Secure Boot is a Windows feature that ensures your computer boots up using trusted Microsoft software, and to ensure that any malicious software does not load at the same time.

Certificates issued in 2011 will begin to expire in June 2026, so Microsoft is starting to push out new ones to eligible PCs for free.

However, that does not include all Windows 10 machines.

“It’s important to note that devices running unsupported versions (Windows 10 and older, excluding those who have enrolled in Extended Security Updates) do not receive Windows updates and will not receive the new certificates,” Microsoft said. “We continue to encourage customers to always use a supported version of Windows for best performance and protection.”

The Extended Security Updates program is available to those on Windows 10 who want to opt in for another year of security updates to take them to October 2026. This is available for free if you are signed into a Microsoft account for most users.

But if you are not part of the ESU program, you will not get the new Secure Boot certificate, which amounts to leaving yet another hole in your computer’s security.

“If a device does not receive the new Secure Boot certificates before the 2011 certificates expire, the PC will continue to function normally, and existing software will keep running,” Microsoft said. “However, the device will enter a degraded security state that limits its ability to receive future boot-level protections.

“As new boot‑level vulnerabilities are discovered, affected systems become increasingly exposed because they can no longer install new mitigations. Over time, this may also lead to compatibility issues, as newer operating systems, firmware, hardware or Secure Boot–dependent software may fail to load.”

Microsoft offers Windows 11 as a free OS update to anyone with a Windows 10 PC, but not all machines out there meet Microsoft’s minimum system requirements. Aside from this update, or opting into the yearlong ESU program, your only way to regain a fully secure computer is to buy a new one that runs Windows 11 – a situation you may not be overly thrilled about, especially if your Windows 10 PC is running fine.