Office 2021 ended support two weeks ago: why Word still opens, and why there is no extension this time

Two weeks ago, on 13 October 2026, Microsoft ended support for Office 2021. If you use Word, Excel, or PowerPoint on an Office Home & Student 2021, Office Home & Business 2021, or Office LTSC 2021 licence, your software stopped receiving security updates that Tuesday. The morning after, Excel opened without a single warning banner, which is why thousands of home laptops and small office PCs across the UK are still running it today as if nothing happened.

Unlike Windows 10, where Microsoft quietly handed home users a reprieve until October 2027, there is no Extended Security Updates programme for Office 2021. Not for home users, and not for businesses willing to pay extra. October 13 was a hard stop. Here is why an unpatched copy of Word or Outlook matters more than people think, and what your actual options cost.

The risk is not opening Word. It is opening somebody else’s file.

When I inspect a computer on my Home Device Security Plan (£10 a month per device) or carry out a Windows security audit for a company, the owner often asks why a word processor even needs security updates. If it typed letters fine in 2022, why would it not type letters fine in 2027?

If you only ever opened plain text files you wrote yourself on an unplugged machine, it would not matter at all. In real life, Word, Excel, and Outlook spend all day parsing complex files sent to you by strangers: supplier invoices, CVs, tender spreadsheets, and email attachments. For twenty years, flaws in how Office unpacks fonts, embedded objects, and table formatting have been one of the main ways attackers get code to run on a Windows PC without you even clicking “Enable Macros”.

Now that Office 2021 is retired, every time Microsoft patches a newly discovered file-parsing hole in Office 2024 and Microsoft 365 on Patch Tuesday, attackers reverse-engineer that patch the same afternoon to see what it fixed, knowing every copy of Office 2021, 2019, and 2016 still has that exact hole wide open.

Where every version of Microsoft Office stands in October 2026

Because Microsoft sells perpetual “buy once” licences alongside monthly subscriptions under almost identical names, half the people I speak to are not sure which one is sitting on their hard drive. The current support dates look like this:

Office Version	Licence type	Security updates end	Status in late October 2026
Office 2016 & Office 2019	One-off purchase	Ended 14 Oct 2025	Unpatched for a year; automatic Cyber Essentials fail
Office 2021 (Home, Business & LTSC)	One-off purchase	Ended 13 Oct 2026	Out of support; no ESU extension available
Visio 2021 & Project 2021	One-off purchase	Ended 13 Oct 2026	Often forgotten on single laptops; fails business audits
Office 2024 (Home & Home/Business)	One-off purchase	9 Oct 2029	Only supported buy-once version left on Windows & Mac
Microsoft 365 Apps	Monthly/annual sub	Ongoing (Oct 2028 on Win 10)	Supported as long as the subscription and OS stay current

The forgotten Visio copy and the £19 product-key trap

Two things catch people out when they try to sort this out in a hurry.

In small offices, the main staff laptops might already be using Microsoft 365 Business Standard, so the director assumes the company is clear. Then we run a software inventory for a Cyber Essentials Danzell check and find two copies of standalone Visio 2021 or Project 2021 installed on the engineers’ machines, or an old copy of Office 2019 left on a reception PC next to the new apps. Under Cyber Essentials, any unpatched software sitting on an in-scope machine fails the assessment, even if nobody opened that icon this week.

At home, the trap is cheap licence keys. Search online for Office 2024 today and you will see dozens of websites selling “lifetime” keys for £19 or £29. Almost all of those are unauthorised volume-licence keys (MAK or LTSC keys meant for corporate servers) being resold in breach of Microsoft’s terms. They activate on day one, and six months later Microsoft revokes the volume key in a batch sweep and leaves your copy of Word deactivated when you are trying to finish a document.

Your three honest choices if you are on Office 2021

If you have a machine running Office 2021 (or 2019), you do not have to pay Microsoft a monthly rent forever if you do not want to. You have three clean options.

First, if you only use Word and Excel at home to write letters, track a household budget, and open the occasional school or council attachment, install LibreOffice. It is free, open-source, reads and writes `.docx` and `.xlsx` files cleanly, and gets regular security patches without costing a penny.

Second, if you want proper Microsoft Word and Excel without a monthly subscription, buy a genuine retail copy of Office Home 2024 (£119.99 for one PC or Mac, without Outlook) or Office Home & Business 2024 (£249.99, which includes classic Outlook and commercial usage rights). That buys you security updates until 9 October 2029. Just make sure you completely uninstall Office 2021 before installing 2024 so the old unpatched components do not linger on the disk.

Third, if you are a business that already pays for Microsoft 365 email, check whether your plan includes the desktop apps. Business Standard (Microsoft’s UK site now lists it with Copilot at £18.10 per user a month ex VAT, paid yearly) and Business Premium include the full desktop suite for five devices per person, though you still need an independent backup for the files you store in it.

Common questions

How do I check which version of Office is installed on my PC?
Open Word or Excel, click Account in the bottom-left corner of the startup screen (or File → Account from inside a document), and look under Product Information. It will state clearly whether you have Microsoft 365, Office 2024, Office 2021, or an older release.

Does Office 2021 still work after 13 October 2026?
Yes. Your documents will still open, edit, and save. The problem is that Microsoft will never issue another security patch for it, leaving it vulnerable to malicious documents, spreadsheets, and email attachments.

Can I install Office 2024 on a Windows 10 computer?
Yes. Microsoft lists both Windows 11 and Windows 10 for Office 2024, though ARM-based PCs need Windows 11. The catch is Windows 10 itself, which now only gets security fixes through the Consumer ESU programme until 12 October 2027, so plan the Windows upgrade alongside the Office one.

If you want your office machines audited for leftover copies of Office 2019, 2021, or Visio before a Cyber Essentials renewal, see my Windows Security Audits. If it is your own computer at home, have a look at my Home Device Security Plan (£10 a month per device) or drop me a message and I will help you check what is installed.