Three Clocks Stop on Tuesday

October 13 is the last day Microsoft issues a security fix for Office 2021, for Windows 10 on paid extended updates, and for Windows Server 2012. Nothing stops working, which is exactly what makes it easy to miss. Two of the three can be extended. One cannot.

Next Tuesday is October 13. It is Microsoft's monthly update day, and it is also the day three separate support clocks run out. If any of the three is yours, Tuesday is the last day that software gets a security fix. Our interest, stated up front: we sell and support Microsoft licensing and we replace hardware. Almost everything below either costs you nothing or sends money our way. Read it knowing that. The technical part — you can skip this box From Microsoft's Extended Security Updates lifecycle FAQ, read October 8, 2026. Windows 10 reached End of Extended Support on October 14, 2025, which is also its Extended Security Updates start date. Year 1 of those updates ends October 13, 2026. Year 2 ends October 12, 2027 and Year 3 ends October 10, 2028 — so Year 1 is the one expiring, and Years 2 and 3 remain available to buy. Qualifying editions are "Enterprise, Education, and Pro in Commercial use." Windows Server 2012 and 2012 R2 reached End of Extended Support on October 10, 2023, with Year 1 ending October 8, 2024, Year 2 ending October 14, 2025, and Year 3 ending October 13, 2026 — the final year listed; the FAQ shows no Year 4. Microsoft describes the program as "a last resort paid option" covering "Critical and/or Important security updates up to three years after the product's End of Extended Support date," and states that "ESUs do not include new features, customer-requested non-security updates, or design change requests." Separately, Microsoft's Office 2021 end-of-support page states that "Support for Office 2021 will end October 13, 2026," that Microsoft then stops providing technical support, bug fixes and security fixes including for vulnerabilities found later, that "All of your Office 2021 apps may continue to function," and that continuing to use it "could expose yourself to serious and potentially harmful security risks." The volume-licensed edition, Office LTSC 2021, carries a mainstream end date of 10/14/2026 6:59:59 AM Pacific in Microsoft's lifecycle table; the two Microsoft pages express it differently, and both land in the same week. What that actually means "End of support" does not mean the software stops. Microsoft's own wording is that the apps "may continue to function." What stops is the repairs. The program keeps opening on Wednesday morning and quietly stops being fixed. "Extended Security Updates" is a paid extension, not a product. Microsoft calls it "a last resort paid option." It buys security patches and nothing else — no features, no bug fixes, no support calls. Three clocks, and only two of them can be wound again. Which one is yours Office 2021. Bought outright, probably in 2021 or 2022, still opening fine. Tuesday is its last security fix. Windows 10 on paid extended updates. If you bought a year of updates last October, that year ends Tuesday. Year two runs to October 2027 and has to be purchased. Windows Server 2012 or 2012 R2. This is the one with no next step. Tuesday is the end of year three, and Microsoft lists no year four. After Tuesday that machine does not get another patch from Microsoft at any price. What to do before Tuesday, and it starts with looking Open Word, click File, then Account. It names the version. If it says Office 2021, you are on this clock. Type winver into the Start menu. It names the Windows version. Windows 10 means Tuesday matters to you. Then the one nobody wants to do: find out whether there is a physical server, and what runs on it. Not the cloud — the box in the closet or the rack. Plenty of twenty-person firms have one holding a single application nobody has touched in years, and it is usually the oldest thing in the building. The honest ranking If you have a Server 2012 machine, deal with that first. It is the only item here with no extension available at any price, and the answer to it is a replacement plan rather than a purchase. Everything else is a budget conversation rather than an emergency. Nothing breaks Wednesday morning. It stops being fixed, and the gap compounds quietly from there — which is a reason to put it in next quarter's plan, not a reason to panic this weekend. If we manage your machines, you will have had this conversation already. If you have not had it, that is worth a call either way.