Microsoft has officially terminated free security support for Windows 10 as of 14 October 2025, a decade after the operating system’s launch in July 2015. The move leaves hundreds of millions of users worldwide vulnerable to cyber threats unless they upgrade to Windows 11, purchase extended security updates, or risk operating unsupported devices that will no longer receive critical patches against newly discovered vulnerabilities.
According to the latest market data from StatCounter, Windows 10 still accounts for approximately 32-41% of all Windows installations globally as of September-October 2025, representing hundreds of millions of devices. In the UK alone, consumer advocacy group Which? estimates that around 5 million computer users continue to operate Windows 10 devices, with roughly a quarter intending to continue using the operating system despite the security risks.
“Our research suggests millions of people may be unprepared for the phasing out of Windows 10,” said Lisa Barber, editor of Which? Tech magazine. “If you don’t act, you could become more vulnerable to hackers and scams.”
Security Implications
Without ongoing security patches, Windows 10 systems become increasingly attractive targets for cybercriminals who actively seek out and exploit unpatched vulnerabilities. Scott Walker, Chief Architect at Orange Cyberdefense, noted that Windows 10 already accounted for the majority of high and critical vulnerabilities among Microsoft’s operating systems even before support ended.
“Windows 10 was already a hotbed for vulnerabilities; our 2025 Security Navigator report previously found that the operating system accounted for the majority of high and critical vulnerabilities, out of all Windows OS versions,” Walker stated. “With Microsoft sunsetting support on 14th October, this problem will only worsen. It’s critical for companies to update ahead of the deadline.”
Microsoft executive Yusuf Mehdi emphasised the risks in a blog post, noting that “while these devices will continue to function, they will no longer receive regular security updates, making them more vulnerable to cyber threats, such as malware and viruses”. Applications running on Windows 10 may also experience decreased functionality as software developers phase out support for the older operating system.
Extended Security Update Options
Microsoft is offering Extended Security Updates (ESU) for Windows 10, marking the first time such a programme has been available to consumers rather than exclusively to businesses. The ESU programme provides critical security patches for up to three years, until October 2026 for the first year, with options to extend further at increasing costs.
For businesses, ESU pricing starts at approximately £58-61 per device for the first year, with costs expected to double annually for subsequent years. Educational institutions and non-profit organizations can access ESU for approximately £0.90 per device initially, though this pricing has been subject to adjustment.
Importantly, Microsoft has confirmed that Microsoft Defender Antivirus will continue to receive security intelligence updates until at least October 2028, providing some ongoing protection against malware even on unsupported Windows 10 systems. Microsoft 365 applications will also receive security updates until October 2028, with feature updates available until August 2026.
Business Impact
The Windows 10 end-of-support deadline creates particular challenges for businesses that must balance security requirements against hardware refresh budgets. Many organisations were forced to purchase additional laptops during the pandemic to support remote work, disrupting normal hardware refresh cycles and leaving them unprepared for the transition to Windows 11-compatible equipment.
Dave Adamson, solutions director at Creative ITC, stated that “the end of Windows 10 support shouldn’t come as a surprise, yet many organisations remain unprepared. Planning gaps, legacy dependencies and budget constraints continue to delay migration, even where devices are technically capable of upgrading”.
Sectors designated as critical national infrastructure, including government, financial services, and energy utilities, face particular risks due to reliance on legacy IT architecture that may not be compatible with newer operating systems. Organisations continuing to use Windows 10 after the end-of-support date may face compliance issues with regulations such as GDPR and industry-specific data protection requirements.
Despite Windows 11 having been available since October 2021, adoption has been slower than anticipated. Research from ControlUp covering over 750,000 Windows endpoints found that while 88% of organisations still running Windows 10 have devices technically capable of upgrading, approximately 82% had yet to initiate the transition as of mid-2024.
