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You need to make one small change to the Windows registry.
For more than three years, this change was documented at Microsoft’s support website, but the company removed those instructions in December 2024. (Here’s an archived version of that support article.) This change tells the Windows 11 Setup program to skip the check for compatible CPUs and to allow installation on a PC with an older TPM (version 1.2). The usual warnings apply when working with the registry; I recommend you make a complete backup before proceeding.
Open Registry Editor (Regedit.exe) and navigate to the following key:
HKEY_LOCAL_MACHINESYSTEMSetupMoSetup
If the MoSetup key doesn’t exist, you need to create it. Right-click the node for HKEY_LOCAL_MACHINESYSTEMSetup in the left-hand navigation pane, then choose New > Key. Name it MoSetup and press Enter.
Also: Wiping your Windows laptop? Here’s the simplest way to erase all personal data
Select the MoSetup key and then right-click in any empty space in the pane on the right. Choose the option to create a new DWORD value. (Don’t choose the QWORD option!)
Replace the default name for that value by typing the text AllowUpgradesWithUnsupportedTPMOrCPU, and then press Enter. Then double-click the new value and change the “Value data” box to 1. The result should look like this:
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On the PC you want to upgrade, go to the Windows 11 Download page (aka.ms/DownloadWindows11) and choose the option at the bottom of the page, “Download Windows 11 Disk Image (ISO) for x64 devices.” Save the ISO file in your Downloads folder.
Note that this is a big file. Depending on the speed of your internet connection, the download could take a while.
Also: Your complete Windows 11 upgrade guide: Everything to know – before you ditch Windows 10
For those running Windows with a non-US language, you might run into problems during the installation process.
The default download is English (United States) but you also have the option to choose English (International) when prompted for a product language. Several readers with Windows 10 PCs configured to use English (UK) have reported that choosing the wrong language results in an upgrade that did not allow them to keep installed apps and data files. If that happens to you, back out of the upgrade, download the other language option, and try again.
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After the download completes, open File Explorer and double-click the ISO file you downloaded in the previous step. Doing so mounts the file as a virtual DVD drive in its own folder, with its own drive letter.
If you’ve installed an alternative file compression app like 7-Zip, you might get an error message complaining that the file ‘Autorun.dll’ cannot be loaded. If you see that error, right-click the ISO file and choose Open With > Windows Explorer.
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In File Explorer, find the Setup.exe file in the virtual drive you opened in the previous step and double-click it to begin the upgrade. You’ll see a dialog warning you in scary language about compatibility issues and the possibility that performing an upgrade will mean you are not entitled to future updates.
You can safely click Accept to move past 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 box, 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).
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.
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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.
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 new 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!
- Download Rufus from the developer’s site or from the Microsoft Store and run the app.
- In Rufus, choose your USB drive and then choose the “Disk or ISO image” option.
- 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.)
- Click Start.
- 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.
- Click OK to accept those changes and then click Start to begin creating the bootable installation drive.
If Setup quits unexpectedly with an error message, try again but choose this option instead.
Screenshot by Ed Bott/ZDNET
Also: Consumer Reports slams Microsoft for Windows 10 mess, urges extension of free updates
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.
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’ve set up a special inbox just for this feedback: Win11Upgrade [at] realworldwindows.com. 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 two years I have been keeping this guide updated.
