"It Has Always Worked" Isn't a Support Plan

Today, October 13, 2026, two Microsoft milestones fall on the same day. The first year of paid security updates for business Windows 10 PCs ends, and so does the final year of paid updates for Windows Server 2012 and 2012 R2. It's also Microsoft's regular monthly security update day, the second Tuesday of the month that people in IT call Patch Tuesday.¹

If you own a small business, you may not have heard any of this. That's normal. The machine on the front desk or in the back office still turns on, the software still opens, and nothing looks different. I've heard the same sentence from owners fifty times: "It has always worked." I understand why that feels like proof, and it's why these situations catch people off guard.

What "no longer supported" really means

A system that has lost support from its maker doesn't stop working. Microsoft ended support for Windows 10 on October 14, 2025. The PCs still run. What changed is that Microsoft no longer provides technical support, feature updates, or quality updates "including security and reliability fixes."²

Fixes for the things that make a computer crash or misbehave stop coming. Nobody at the vendor is looking at your problem anymore.

What happens when you need to change something

The trouble shows up as a steady run of things that used to be easy and suddenly aren't.

You buy a new printer, and the manufacturer's driver doesn't support your old operating system. You upgrade another program, say your accounting software, and the new version won't install on the old machine. A vendor you rely on changes its product and no longer works with what you're running. Your insurance renewal arrives with a question about whether your systems are still supported, and you have to answer honestly.

Then there's hardware failure. A drive dies or a power supply gives out, and the replacement machine can't run the old operating system, or the old operating system can't be installed on new hardware at all. A repair that should take an afternoon turns into a project nobody planned for, and your staff sit idle while it happens.

Each of these is small by itself. The common thread is that you're stuck with a system that can't be updated and can't easily be replaced, and the decision gets made on someone else's schedule, usually during a bad week.

The specialized equipment problem

This is the case I run into most often. A lab instrument or a manufacturing machine is controlled by a PC. That PC runs an older version of Windows because the equipment vendor's software only works there. The machine cost a lot and does its job well, and the vendor either hasn't released a newer version of the software or wants a large sum for the upgrade.

Nobody made a bad decision here. The equipment is fine. The computer attached to it is the part that has aged out, and you can't simply swap it for a current PC because the software won't run on one.

Systems like this often can't be replaced this year. That's fine, and it's why the second step below exists.

What Windows 10 and Server 2012 deadlines mean for you

Businesses can pay Microsoft for Extended Security Updates, called ESU, for Windows 10 Enterprise, Education and Pro used in a business. The first year ends today. Year 2 ends October 12, 2027, and Year 3 ends October 10, 2028. Three years is the maximum.³

The price is $61 per device for Year 1, and Microsoft says "the price doubles every consecutive year." That works out to $122 for Year 2 and $244 for Year 3. ESU is also cumulative. Microsoft's wording is "If you decide to purchase the program in Year Two, you have to pay for Year One too." You can't skip the early years and buy in later at the current price.²

That money gets you only critical and important security updates. No new features and no general technical support. If a printer driver breaks or a program misbehaves, you're no better off than you were.

Microsoft describes ESU as "a last resort paid option for customers who need to run certain legacy Microsoft products past the end of support. They are not intended as a long-term solution, but rather as a temporary bridge to stay secure while one migrates to a newer, supported platform."³ I'd take that at face value. ESU only helps if you know what comes next. If you're paying for ESU, you should also have a date and a budget for what replaces the PC.

If your Windows 10 machines are home (consumer) editions, the ESU program for those runs through October 12, 2027.⁴ That's a separate track from the business program.

For Windows Server 2012 and 2012 R2, the third and final year of paid ESU also ends today. ESU never covers more than three years after end of support, so this is the end of the paid extension program for those servers.³ If you have one in a closet or a back room that "just runs the shared files" or the old database, find out now.

Step one: find out what you actually depend on

The first step takes an afternoon. Make a list of the computers and software your business can't operate without. Include the odd ones, like the PC attached to equipment or the server nobody has logged into in a year.

For each item, find out whether its maker still supports it. Look at the vendor's website, or ask your IT provider to check. The answer is yes or no, and if support is ending, a date. Write that date down.

Most owners are surprised in one direction or the other. Some find that an item they worried about is fine. Others discover a server that's been out of support for years.

Step two: isolate what can't be replaced yet

For anything that is out of support and can't be replaced right now, the goal is to let it do its one job without letting everything else reach it.

This approach comes from federal guidance. NIST, the US National Institute of Standards and Technology, addresses systems that can't be patched in its publication SP 800-40 Rev. 4, including when the vendor no longer provides patches. Its answer is "isolation or other methods to mitigate the risk," for example "using firewalls and network segmentation to isolate vulnerable assets."⁵

CISA, the US Cybersecurity and Infrastructure Security Agency, lists the use of unsupported (end-of-life) software in critical infrastructure as a "bad practice," and says it's "especially egregious in technologies accessible from the Internet."⁶

In practice, isolation means the machine sits on its own section of your network. The lab instrument's PC can talk to the instrument and to the one place it saves its results. It can't browse the web or receive email, and the rest of your office computers can't reach it. Your IT provider or whoever manages your network can set this up with the router and firewall you may already own. It's usually a modest project, far smaller than replacing the equipment.

Isolation also helps with reliability. A machine that does one job and nothing else is less likely to be disturbed by changes elsewhere on your network.

Budget the replacement before it becomes an emergency

Isolation and ESU both buy time, but the system will eventually need to be replaced.

Put it in the budget as a planned expense. Ask the equipment vendor what a supported version of their software costs and what hardware it needs. Get a rough number for replacing each old PC and server on your list. A planned replacement spread across a budget cycle is a normal expense. The same replacement forced by a failure on a Monday morning costs more and takes longer, because you're making every decision in a hurry.

What I'd do this week

• Make the list of systems your business depends on, including the ones attached to equipment.
• Check each one for current vendor support and write down the end date.
• If you have Windows 10 business PCs, decide whether ESU is worth buying as a bridge, and remember it's cumulative.
• If you have a Windows Server 2012 or 2012 R2 machine, plan its replacement now, since the paid extension ends today.
• Isolate anything unsupported that has to stay in service, and write down who owns it.
• Ask your insurance contact whether they'd like to see your list of supported systems at renewal.
• Set a replacement date and a budget line for each item, even if the date is two years out.

It's much easier to know what you have and decide what happens next on a quiet Tuesday, while you still have choices, than after something has stopped working.