Windows 10 End of Life: A Growing Cyber Risk for Businesses 11th September 2025 Microsoft has confirmed it will end support for Windows 10 on October 14, 2025, a move that may appear routine but carries significant cybersecurity implications for businesses that don’t act. While many users and organisations remain fond of the operating system’s familiarity, continuing to run Windows 10 post-EOL introduces real and growing risks, especially from an SME risk management perspective. If your business or clients are still using Windows 10 beyond the retirement date, it’s essential to understand the exposure and plan accordingly. What Happens When Support Ends? Once Windows 10 reaches end of life (EOL), Microsoft will: Cease issuing security patches and updates Halt technical support and bug fixes Discontinue updates for platform integration (e.g. browser, Defender) Remove the OS from its officially supported list for many Microsoft 365 and Azure services In effect, any newly discovered vulnerability, no matter how critical, has the potential to remain unpatched and exploitable. The Cyber Risk Landscape After EOL Here’s how the security profile of a Windows 10 device deteriorates after October 2025: Unpatched Vulnerabilities Cyber attackers actively monitor end-of-life timelines and often target unsupported systems: Exploits for old OS versions become widespread and weaponised. Attackers can rely on the fact that no future fixes are coming. Malware kits are updated to take advantage of known weaknesses (e.g. RDP brute force, SMB exploitation). Increased Exposure to Zero-Days If a zero-day exploit affects both Windows 10 and newer systems, only the latter will receive a patch. Businesses on Windows 10 are: Stuck with known vulnerabilities Reliant on third-party endpoint tools, which themselves may also drop support over time Compatibility Gaps: Microsoft 365 and Cloud Access Microsoft has confirmed that Microsoft 365 apps (Word, Excel, Outlook, etc.) will technically still run on Windows 10 after October 2025, but without support or updates. This creates a deteriorating compatibility picture: Teams, OneDrive, and Outlook may behave inconsistently. Conditional access policies in Microsoft Entra ID (formerly Azure AD) may restrict login from unsupported OS versions. Browser support will eventually be pulled, cutting off access to cloud tools (e.g. Salesforce, Google Workspace, Xero) or forcing use of insecure, outdated browsers. In practical terms, this means cloud infrastructure, the backbone of many SME operations, will gradually become less reliable, less secure, and ultimately unsupported on Windows 10. Regulatory Implications Cyber risk is no longer just a technical issue; it’s a compliance and financial concern: Regulators could interpret continued use of Windows 10 as a breach of data protection obligations — especially if an incident involves personal or sensitive data. Standards frameworks (ISO 27001, Essential Eight, NIST) explicitly require systems to be patched and supported to comply with maturity standards – essential when others rely on your services. Migration Challenges for SMEs For small businesses operating under strained cash flow, migrating to a new operating system might sound daunting — especially if they’re on a mix of older devices or dependent on legacy applications. The most common friction points include: Hardware Compatibility Windows 11 requires newer CPUs, TPM 2.0, and Secure Boot. Older machines (pre-2018) may be unable to upgrade — necessitating replacement. Legacy Applications Some bespoke or industry-specific tools may not yet support Windows 11. Outdated drivers or printer software can complicate upgrades. Training and Disruption Windows 11 introduces UI and workflow changes. Staff may need time and training to adjust, potentially increasing help desk traffic in the short term. However, most of these challenges can be resolved with a structured approach: run a compatibility audit, pilot the upgrade with 1–2 users, and stagger the rollout across your workforce. Risk Mitigation Options If you’re unable to migrate before October 2025, the following steps can reduce exposure temporarily: Where possible, segment Windows 10 devices from your wider network Use non-administrative accounts for daily use Remove or disable high-risk services like SMBv1 and RDP Implement application whitelisting Ensure all third-party applications are fully updated Maintain a robust offline backup strategy Deploy advanced endpoint detection and response (EDR) tools with active threat monitoring These measures help reduce the attack surface but do not eliminate the fundamental issue of unsupported software. Strategic Opportunity: Modernisation Rather than viewing the retirement of Windows 10 as a burden, consider it a catalyst for modernisation: Where possible, consolidate systems into cloud-native platforms Roll out zero trust principles with device compliance enforcement Leverage Windows Autopilot and Intune for simplified deployment A transition to Windows 11 also opens the door to stronger, more consistent policy enforcement, especially around endpoint security and identity access management – common areas of compromise Final Word for Business Leaders If you or your clients are still running Windows 10: Start planning now. Don’t wait for October 2025 to trigger action. Audit your devices & users, and create a migration plan. Speak with your IT provider or MSP about hardware compatibility, app support, and security posture.