Windows 10 support has ended: what does a Northern Ireland business need to do?

Windows 10 reached the end of support on 14 October 2025: Microsoft no longer provides security updates, feature updates or technical support for it ^{1Source 1Windows 10 Enterprise and Education lifecycle — Microsoft Learn, 1 November 2024.learn.microsoft.com/en-us/lifecycle/products/windows-10-enterprise-and-educationAccessed 3 November 2026See in Sources2Source 2Windows 10 Extended Security Updates (ESU) — Microsoft Learn, 17 November 2025.learn.microsoft.com/en-us/windows/whats-new/extended-security-updatesAccessed 3 November 2026See in Sources}. A Northern Ireland business still running it has three choices. Upgrade each PC to Windows 11 for free if it meets the hardware requirements, replace the PCs that don't, or buy Microsoft's Extended Security Updates (ESU) as a bridge, which Microsoft prices for organisations at US$61 per device for the first year, doubling each year for a maximum of three years ^{2Source 2Windows 10 Extended Security Updates (ESU) — Microsoft Learn, 17 November 2025.learn.microsoft.com/en-us/windows/whats-new/extended-security-updatesAccessed 3 November 2026See in Sources}. Running Windows 10 without updates is not a free option: the NCSC says the only fully effective way to remove the risk of an unsupported product is to stop using it ^{3Source 3Obsolete products — National Cyber Security Centre (NCSC), device security guidance, reviewed 13 May 2025.www.ncsc.gov.uk/collection/device-security-guidance/managing-deployed-devices/obsolete-productsAccessed 3 November 2026See in Sources}, unsupported software in scope fails Cyber Essentials ^{4Source 4Cyber Essentials: Requirements for IT Infrastructure v3.3 — National Cyber Security Centre (NCSC), April 2026.www.ncsc.gov.uk/files/cyber-essentials-requirements-for-it-infrastructure-v3-3.pdfAccessed 3 November 2026See in Sources}, and insurers now ask whether your operating systems are supported ^{5Source 5Goodbye Windows 10 — Brit Insurance (insurer), 2026.www.britinsurance.com/news/goodbye-windows-10/Accessed 3 November 2026See in Sources}.

The short version

• Since 14 October 2025 Windows 10 gets no security fixes. Every new vulnerability found stays open on every Windows 10 PC you keep ^{1Source 1Windows 10 Enterprise and Education lifecycle — Microsoft Learn, 1 November 2024.learn.microsoft.com/en-us/lifecycle/products/windows-10-enterprise-and-educationAccessed 3 November 2026See in Sources2Source 2Windows 10 Extended Security Updates (ESU) — Microsoft Learn, 17 November 2025.learn.microsoft.com/en-us/windows/whats-new/extended-security-updatesAccessed 3 November 2026See in Sources}.
• Business ESU buys up to three more years of security-only updates, at US$61 per device for year one, doubling each year, and you can't skip earlier years ^{2Source 2Windows 10 Extended Security Updates (ESU) — Microsoft Learn, 17 November 2025.learn.microsoft.com/en-us/windows/whats-new/extended-security-updatesAccessed 3 November 2026See in Sources}.
• Most PCs bought since about 2018 can run Windows 11; the sticking points are TPM 2.0, Secure Boot and the processor. Microsoft's PC Health Check app tells you per machine ^{6Source 6Windows 11 requirements — Microsoft Learn, updated 21 July 2026.learn.microsoft.com/en-us/windows/whats-new/windows-11-requirementsAccessed 3 November 2026See in Sources}.
• Cyber Essentials v3.3 requires unsupported software to be removed from in-scope devices or cut off from the internet, so Windows 10 PCs block certification ^{4Source 4Cyber Essentials: Requirements for IT Infrastructure v3.3 — National Cyber Security Centre (NCSC), April 2026.www.ncsc.gov.uk/files/cyber-essentials-requirements-for-it-infrastructure-v3-3.pdfAccessed 3 November 2026See in Sources}.

What exactly ended on 14 October 2025?

Microsoft's lifecycle page is plain: Windows 10 reached end of support on 14 October 2025, and version 22H2 was its final release ^{1Source 1Windows 10 Enterprise and Education lifecycle — Microsoft Learn, 1 November 2024.learn.microsoft.com/en-us/lifecycle/products/windows-10-enterprise-and-educationAccessed 3 November 2026See in Sources}. From that date Microsoft no longer provides technical support, feature updates or quality updates, including security and reliability fixes ^{2Source 2Windows 10 Extended Security Updates (ESU) — Microsoft Learn, 17 November 2025.learn.microsoft.com/en-us/windows/whats-new/extended-security-updatesAccessed 3 November 2026See in Sources}. The PCs keep working, but each security flaw discovered from now on is patched on Windows 11 and left open on Windows 10, which the NCSC notes "increases the likelihood that exploitable vulnerabilities will become known by attackers" ^{3Source 3Obsolete products — National Cyber Security Centre (NCSC), device security guidance, reviewed 13 May 2025.www.ncsc.gov.uk/collection/device-security-guidance/managing-deployed-devices/obsolete-productsAccessed 3 November 2026See in Sources}.

Plenty of machines are still affected. In October 2026, 13.8% of desktop Windows web traffic in the UK still came from Windows 10, against 86% from Windows 11 ^{7Source 7Desktop Windows version market share, United Kingdom, October 2026 — StatCounter Global Stats (share of page views).gs.statcounter.com/windows-version-market-share/desktop/united-kingdomAccessed 3 November 2026See in Sources}.

How much do Windows 10 Extended Security Updates cost a business?

Microsoft publishes the business price in US dollars; UK resellers quote it in sterling at their own rates, so ask for a pound figure. Only whole years can be bought, devices must be on Windows 10 version 22H2, and ESU includes security updates only: no new features and no technical support ^{2Source 2Windows 10 Extended Security Updates (ESU) — Microsoft Learn, 17 November 2025.learn.microsoft.com/en-us/windows/whats-new/extended-security-updatesAccessed 3 November 2026See in Sources}. Microsoft runs a separate consumer programme for home PCs, extended in June 2026 to run until 12 October 2027 at a one-off US$30 or free with settings sync or Microsoft Rewards points ^{8Source 8Windows 10 consumer Extended Security Updates — Microsoft UK.www.microsoft.com/en-gb/windows/extended-security-updatesAccessed 3 November 2026See in Sources9Source 9Microsoft extends free Windows 10 security updates for consumers to October 2027 — Help Net Security, 26 June 2026 (trade press).www.helpnetsecurity.com/2026/06/26/microsoft-windows-10-free-security-updates-esu-program/Accessed 3 November 2026See in Sources}; it is not designed for managed business fleets.

Should you buy ESU or replace the PCs?

ESU is a bridge, not a destination. Over three years it costs about US$427 per device, by which time the PC is three years older and still has to be replaced. It makes sense for a small number of machines that can't be upgraded yet: a PC tied to a piece of equipment or an application that only runs on Windows 10, or a fleet whose replacement is already funded for next year.

What are the Windows 11 hardware requirements?

• A 1 GHz or faster processor with two or more cores, on a compatible 64-bit processor ^{6Source 6Windows 11 requirements — Microsoft Learn, updated 21 July 2026.learn.microsoft.com/en-us/windows/whats-new/windows-11-requirementsAccessed 3 November 2026See in Sources}.
• 4 GB of memory or more, and 64 GB of storage or more ^{6Source 6Windows 11 requirements — Microsoft Learn, updated 21 July 2026.learn.microsoft.com/en-us/windows/whats-new/windows-11-requirementsAccessed 3 November 2026See in Sources}.
• UEFI firmware that is Secure Boot capable, and a Trusted Platform Module (TPM) version 2.0 ^{6Source 6Windows 11 requirements — Microsoft Learn, updated 21 July 2026.learn.microsoft.com/en-us/windows/whats-new/windows-11-requirementsAccessed 3 November 2026See in Sources}.
• A DirectX 12-compatible graphics card and a 720p display of 9 inches or larger ^{6Source 6Windows 11 requirements — Microsoft Learn, updated 21 July 2026.learn.microsoft.com/en-us/windows/whats-new/windows-11-requirementsAccessed 3 November 2026See in Sources}.

In practice the processor is what rules older machines out, and Microsoft now points businesses to its PC Health Check app rather than a list of supported chips ^{6Source 6Windows 11 requirements — Microsoft Learn, updated 21 July 2026.learn.microsoft.com/en-us/windows/whats-new/windows-11-requirementsAccessed 3 November 2026See in Sources}. Many PCs fail only because TPM 2.0 or Secure Boot is switched off in the firmware; turning them on makes the machine eligible. Check every PC before you budget, and don't guess from the purchase date.

What does running Windows 10 mean for Cyber Essentials and cyber insurance?

Cyber Essentials, the UK Government's minimum standard, is explicit. The April 2026 requirements (version 3.3) say software on in-scope devices must be licensed and supported, and must be removed from devices when it becomes unsupported, or removed from scope by using a defined sub-set that prevents all traffic to or from the internet ^{4Source 4Cyber Essentials: Requirements for IT Infrastructure v3.3 — National Cyber Security Centre (NCSC), April 2026.www.ncsc.gov.uk/files/cyber-essentials-requirements-for-it-infrastructure-v3-3.pdfAccessed 3 November 2026See in Sources}. A Windows 10 PC with no ESU on your main network therefore fails the assessment, and the same document requires critical and high-risk fixes to be applied within 14 days of release, which is impossible when no fixes are released ^{4Source 4Cyber Essentials: Requirements for IT Infrastructure v3.3 — National Cyber Security Centre (NCSC), April 2026.www.ncsc.gov.uk/files/cyber-essentials-requirements-for-it-infrastructure-v3-3.pdfAccessed 3 November 2026See in Sources}.

Cyber insurers look at the same thing. Underwriters increasingly ask about supported operating systems and patching on the proposal form; one Lloyd's insurer describes keeping systems current as something that "may influence coverage terms positively" ^{5Source 5Goodbye Windows 10 — Brit Insurance (insurer), 2026.www.britinsurance.com/news/goodbye-windows-10/Accessed 3 November 2026See in Sources}, and the NCSC warns that if you claim security measures are in place when they are not, the insurer may not be obliged to pay a claim ^{10Source 10Cyber insurance guidance — National Cyber Security Centre (NCSC), 2020.www.ncsc.gov.uk/guidance/cyber-insurance-guidanceAccessed 3 November 2026See in Sources}. Check your own policy wording rather than assuming either way.

What should the plan look like?

What does BTNI do about this?

At BTNI, every PC under Managed IT is inventoried and patched on a schedule, so a customer already knows which machines passed PC Health Check and which need replacing, and the Windows 11 moves are part of the roadmap rather than a surprise. If you don't know how many Windows 10 PCs you still have, a free Business Technology Review will tell you, along with what it would cost to put right.