Microsoft discourages Windows 11 upgrades for ‘incompatible’ PCs, but there’s a workaround

When Microsoft released Windows 11 in 2021, it also introduced strict hardware compatibility requirements for the new operating system. If you try to upgrade your Windows 10 PC, the compatibility reviewer built into the new Setup program checks your hardware first. If your CPU is not in the supported models list or if your PC is missing one Trusted platform module (TPM) standard support version 2.0, that upgrade failed.

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For Windows enthusiasts, that compatibility testing was more of a challenge than a hurdle, and they quickly discovered two ways to get around the hardware requirements and enable Windows 11 upgrades on most devices. almost any hardware capable of running Windows 10. (I’ve documented both of those). those methods in a post that has become one of the most popular articles I’ve ever published at ZDNET: How to upgrade an ‘incompatible’ Windows 10 PC to Windows 11: Two options.)

Microsoft officially documents one of those techniques, primarily for the benefit of enterprise customers. Using this technique allows you to perform a Windows 11 upgrade on a system with an incompatible CPU by making a small modification to the registry. The resulting setting is not supported, but it works. However, there is an additional important requirement. The PC that needs to be upgraded must also have TPM enabled. Older TPM 1.2 is fine. No TPM? Sorry, no upgrades.

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The second technique uses a crude but effective hack, replacing the compatibility assessment module (Appraiserres.dll) with a 0-byte file with the same name. The popular Rufus utility performs this modification automatically with just a click of a checkbox, and it works even on PCs that lack a TPM and don’t have the ability to enable Secure Boot. EQUAL A large number of readers have reportedThis technique has worked on even ancient PCs.

Until this week, that is. At the same time, Microsoft deployed it Windows 11, version 24H2 on October 1, it also appears to have tweaked some additional settings that damage the second upgrade option. Yesterday, I heard a reader report that the installer he created using Rufus failed with the following error message:

I was able to reproduce this issue on a virtual machine I created specifically to test this scenario. That VM doesn’t have a TPM and was created using Legacy BIOS instead of UEFI, so it also doesn’t meet Windows 11’s requirements for Secure Boot support.

But in the ongoing cat-and-mouse game between Microsoft and the community of dedicated Windows hackers, this is just a speed bump. After a user reported the issue on GitHub yesterday, Rufus developer Pete Batard quickly provided a workaround.

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For an in-place upgrade, he writes, you need to run a series of commands from an elevated command prompt to make additional registry changes before running Setup.exe. (As Batard notes, these modifications were originally posted by the developers of Win 11 Boot and upgrade FiX KiT.)

reg.exe delete “HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\CompatMarkers” /f 2>NUL

reg.exe delete “HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\Shared” /f 2>NUL

reg.exe delete “HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\AppCompatFlags\TargetVersionUpgradeExperienceIndicators” /f 2>NUL

Reg.exe adds “HKLM \ Software \ Microsoft \ Windows NT \ Currentversion \ AppCompatflags \ Hwreqchk” /f /v hwreqchkvars /t reg_multi_sz /s, /d “sq_securebootcapable = true, sq_securebootenbs = true, sq_olam = MB = 8192, “

reg.exe add “HKLM\SYSTEM\Setup\MoSetup” /f /v AllowUpgradesWithUnsupportedTPMOrCPU /t REG_DWORD /d 1

(I recommend copying those commands Directly from GitHub comments to ensure that they execute without problems.)

After I ran those commands on my test system, the upgrade went without a problem.

According to the discussion in that GitHub issue, the next version of Rufus will contain these tweaks in a batch script that users will need to run manually to bypass the new restrictions on in-place upgrades.

There doesn’t appear to be any changes to the documented method that Microsoft has published. On a PC with TPM and configured with UEFI and Secure Boot, upgrading should be simple, regardless of whether the CPU is supported or not. And as far as I can tell, there’s no compatibility testing on upgrades for systems running Windows 11, so those installations should be fine.

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However, additional compatibility testing on older hardware that lacks a TPM or is configured to use Legacy BIOS instead of UEFI will present a significant usability barrier, especially for users lack of technical background in Windows deployment.

I’m continuing to test these scenarios. If you have any problems with your upgrade, please send me an email with detailed information, including the make and model of your computer and screenshots of any error messages any. I’ve set up a special inbox just for this response: Win11Upgrade [at] realworldwindows.com.