How to upgrade your ‘incompatible’ Windows 10 PC to Windows 11 – for free

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ZDNET’s key takeaways

• Most PCs from the past 15 years can run Windows 11.
• PCs sold with Windows 10 can usually upgrade after a registry edit.
• On older or unusually configured PCs, a third-party utility can work.

Are you the designated PC expert for your family and friends? The next time you get a call asking for help with a Windows PC, check to see which version it’s running. If the System > About page says Windows 10, then they really need your help. 

On Oct. 14, 2025, Microsoft officially ended support for Windows 10. That old PC no longer receives security updates unless you’ve enrolled it in the Extended Security Updates program, which pushes the expiration date out until October 2026. For anyone still running Windows 10 who has ignored Microsoft’s increasingly strident warnings, they’re already several months behind, having missed the important monthly security updates starting in November 2025. 

Also: AI PCs aren’t selling, and Microsoft’s PC partners are scrambling

Trust me — you really don’t want to be doing anything on a PC that’s missing months of security updates. So, it’s time to upgrade, right? Unfortunately, that’s not an easy assignment.

If you try to upgrade to Windows 11 on a PC that’s more than five or six years old, you’ll probably encounter an error message telling you — in no uncertain terms — that that old PC doesn’t qualify because its CPU isn’t on the official list of compatible processors. You will also hit roadblocks if the PC doesn’t have a Trusted Platform Module (TPM) version 2.0, or if the TPM is not enabled.

Also: How to get free Windows 10 security patches on your PC – from now to October 2026

That might be the official policy, but — as with everything Windows-related — it pays to read the fine print. If that PC is less than 10 years old and has sufficient memory and storage, then it’s probably worth keeping, and you can upgrade it.

Those pesky restrictions prevent you from automatically upgrading to Windows 11 using Windows Update or the Windows 11 Installation Assistant. Yet, as hundreds of ZDNET readers have reported just in the last year, there are documented workarounds for most PCs that were originally built for Windows 10.

Over the past few years, Microsoft has played a cat-and-mouse game with enthusiasts, adding occasional speed bumps that make it more difficult to bypass these compatibility checks. There are techniques that allow you to bypass those restrictions on most modern PCs, but some older devices, especially those built using AMD processors, might be out of luck.

The instructions in this article take all those developments into account.

Also: Windows 10 PC can’t be upgraded? You have 5 options – and must act now

These instructions also assume that you have a PC with an x64 CPU (not ARM and not 32-bit), running a retail or OEM edition of Windows 10 (Home or Pro), and that you are signed in as an administrator on the PC you want to upgrade.

You also need sufficient free space on your system drive. The official requirements specify that you need 64GB of free space, but an upgrade should work with a minimum of 25-30GB free. If you don’t have that space free, you’ll need to uninstall apps or remove files to reach the minimum.

Which option should you choose?

Please don’t skip over this section.

This article describes two upgrade options. To take advantage of the workaround described in option 1 below, your computer must meet all the other requirements for Windows 11.

• It must be configured to start up using UEFI, not a legacy BIOS configuration.
• Secure Boot must be supported, although it does not need to be enabled. (But seriously, folks, you should enable Secure Boot.)
• A TPM must be enabled; version 1.2 is OK, but a system without any TPM or with the TPM disabled will fail. Any PC that was originally designed for Windows 10 should include a TPM 2.0.

To check these details on a PC you’re considering upgrading, run the System Information utility, Msinfo32.exe, and look at the System Summary page. Pay special attention to the BIOS Mode value. If it says “Legacy,” you’ll need to reconfigure your system to UEFI mode (and convert your system disk from MBR to GPT partitioning) before you can install Windows 11 as a normal upgrade.

Also: Windows 11 upgrade not working? Try my 5 favorite troubleshooting tricks

To see whether your PC has a TPM enabled, run the Trusted Platform Module Management tool, Tpm.msc.

If your computer includes a TPM and it’s turned on, this app will display information about it. Under the TPM Manufacturer Information heading, check the specification version to confirm that it is 2.0. If there’s no TPM, or if the TPM is disabled in firmware settings, you’ll see a message that says “Compatible TPM cannot be found.”

If you’re unable (or unwilling) to change from Legacy BIOS to UEFI, or if you have an older PC that doesn’t have a TPM option at all, you’ll need to use the second option, which takes advantage of an undocumented hack that allows you to bypass the compatibility checks and complete the upgrade. Skip to the Option 2 section of this post for details on how to use the free Rufus utility to perform this upgrade.

Finally, note that Microsoft added a new set of restrictions beginning with the Windows 11 version 24H2 update. These changes require a CPU that supports specific instructions — SSE4.2 and PopCnt. Most PCs with Intel CPUs from 2009 or later will meet this standard. AMD CPUs from 2013 or later should also meet these requirements.

But it is impossible to upgrade to a supported version of Windows 11 on a PC that was built in 2008 or earlier. For details, see “Microsoft blocked your Windows 11 upgrade? This trusty tool can (probably) fix that.”

Also: Microsoft said these 400 readers couldn’t upgrade to Windows 11. They did it anyway

If you plan to perform a clean installation of Windows 11, you can boot from installation media and run Windows Setup. That option skips the CPU compatibility check completely (but still requires a TPM and Secure Boot support). After the installation completes, you’ll need to reinstall all your apps, restore your data files, and tweak settings to personalize your system preferences.

Want to avoid all that hassle? Choose the option that’s appropriate for your hardware.

Option 1: Use this simple registry edit

With this registry edit, you can bypass CPU checks and accept any TPM version. Please be aware that this option requires that you run the Setup program from within your current Windows installation. You can’t boot from a USB flash drive and upgrade to Windows 11 this way.

This process requires four steps.

Check for errors before proceeding — Windows is frustratingly literal about the contents of the registry, and if you misspell the key or value name, or if you create the required value in the wrong location, your upgrade will fail. Click OK to save your changes, and then restart your PC.

You can safely click Accept to acknowledge that you read this message and continue the upgrade. (For details on what that warning message really means, see Is Microsoft really going to cut off security updates for your ‘unsupported’ Windows 11 PC? Spoiler: They are not going to cut off security updates.) After you click OK on that dialog, your upgrade should proceed without any serious issues.

Also: Why Windows 11 requires a TPM – and how you can get around it

If you’re upgrading from the same edition (Home or Pro), you’ll have three options: You can keep your apps, settings, and files (Full Upgrade); keep your data files but start fresh with apps and settings (Keep Data Only); or start completely fresh (Clean Install). If you don’t see the Full Upgrade option, see the note in Step 2 about language selection. Download the Windows 11 ISO again, choosing the correct language, and try again.  

One last piece of advice: Watch carefully at the beginning of Setup for an option labeled “Change how setup downloads updates.” To increase your chances of a successful upgrade, click that link and choose the “Not right now” option. That should allow Windows Setup to finish faster — you’ll have a chance to download those updates after the upgrade is complete.

If you encounter any difficulties or if the upgrade fails, check this article for detailed advice on what to do to find and fix the problem: Windows 11 upgrade not working? Try my 5 favorite troubleshooting tricks.

Option 2: Use the free Rufus utility

On older PCs without a TPM and on PCs that don’t support Secure Boot and UEFI, you’ll need to use an undocumented hack to bypass the compatibility checker. It is technically possible to do this manually by replacing the Appraiserres.dll file (in the Sources subfolder on the Windows 11 installer drive) with a zero-byte version and then making a series of registry edits. But it’s simpler to use the free, open-source Rufus utility to create installation media (on a USB flash drive) that includes these tweaks automatically.

To get started, download the latest version of Rufus. Versions earlier than 4.6 won’t work, thanks to changes Microsoft made in October 2024 to its compatibility checking tools. For details of how the newer versions work, see Microsoft blocked your Windows 11 upgrade? This trusty tool can (probably) fix that.

In addition, be aware that using Rufus will not allow you to bypass the restrictions on very old PCs that were introduced with Windows 11 version 24H2. If you have a PC with a CPU that lacks support for SSE4.2 and PopCnt instructions, not even Rufus can help. (Of course, any PC that fails that test is probably 15-20 years old and deserves to be retired.)

Also: You can still upgrade old PCs to Windows 11, even if Microsoft says no: Readers prove it

To get started, you’ll need to download the Windows 11 ISO from aka.ms/DownloadWindows11. Choose the option at the bottom of the page, “Download Windows 11 Disk Image (ISO) for x64 devices.” (Although Rufus offers an option to download the ISO file, I recommend that you get it directly from this official page instead.)

Save the ISO file in the Downloads folder of your Windows system drive so you can find it easily. You’ll also need a USB flash drive of at least 16GB in size. You will reformat this drive as part of the process, so back up any data on that drive first — and do not store the Windows 11 ISO here!

1. Download Rufus from the developer’s site or from the Microsoft Store and run the app.
2. In Rufus, choose your USB drive and then choose the “Disk or ISO image” option.
3. Click the Select button and choose the Windows 11 ISO you downloaded earlier (hint: it’s in your Downloads folder). After you make that selection, confirm that the Partition Scheme and Target System options match the system you plan to upgrade. That’s especially important if you’re upgrading an old system with a Legacy BIOS rather than UEFI. (For most PCs built in 2015 or later, the default settings will be correct.)
4. Click Start.
5. In the Windows User Experience dialog, select the first checkbox to remove hardware requirements, as shown in the screenshot below. (If you see an error message about a revoked UEFI bootloader, download a fresh ISO file and start over.) Adjust any other settings as you prefer.
6. Click OK to accept those changes and then click Start to begin creating the bootable installation drive.

After Rufus successfully creates your installer, open that USB drive in File Explorer, and double-click Setup. Do not try to upgrade by booting from that USB drive and performing a clean install; it won’t work.

As is the case with the other option, you’ll see a warning about compatibility issues, with the heading “What needs your attention.” It’s a scare tactic. (For details on what the language in that warning message actually means, see Is Microsoft really going to cut off security updates for your ‘unsupported’ Windows 11 PC?) After you click Accept on that dialog box, your upgrade should proceed without any serious issues.

Several readers have reported that Setup failed prematurely and displayed an error message (“An unsupported operation was attempted”) when run from media created using Windows 11 version 24H2 and the latest version of Rufus. The fix? Watch carefully at the beginning of Setup for an option labeled “Change how setup downloads updates.” Click that link and choose the “Not right now” option, as shown here. That should allow Setup to continue without interruption.

My ZDNET colleague Lance Whitney has more details on the other options available with Rufus in How to install Windows 11 your way (and avoid Microsoft’s restrictions).

If you encounter any difficulties or if the upgrade fails, check this article for detailed advice on what to do to find and fix the problem: Windows 11 upgrade not working? Try my 4 favorite troubleshooting tricks.

Did your upgrade work?

If you’ve tried this upgrade, I want to hear about your experience. If it worked, please share the details. If you run into snags, send me an email so we can figure out what’s going wrong. I’ve set up a special inbox just for this feedback: Win11Upgrade [at] realworldwindows [dot] com.

Also: 9 things I always do after setting up Windows 11 – and why you should too

Be sure to include details — the make and model of your PC and screenshots of any error messages. If you’re able to create a report using the SetupDiag utility, please include that as well — you’ll find detailed instructions in my Windows 11 upgrade troubleshooting guide. 

I can’t reply to every submission, but I read them all, and I am immensely grateful for the reports you provide. That information has been invaluable over the three-plus years I have been keeping this guide updated.