The endless cat-and-mouse game between Microsoft and the community of devoted Windows hackers just took another turn.
When Microsoft released Windows 11 in 2021, it also rolled out strict hardware compatibility requirements for the new operating system. If you tried to upgrade a Windows 10 PC, a compatibility appraiser built into the new Setup program checked your hardware first. If your CPU wasn’t on the list of supported models, or if your PC lacked a Trusted Platform Module (TPM) that supports the version 2.0 standard, that upgrade failed.
Microsoft officially documents one of those techniques, primarily for the benefit of corporate 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 installation is unsupported, but it works. There’s one additional, crucial requirement, however. The PC to be upgraded must also have a TPM enabled. An older TPM 1.2 is fine. No TPM? Sorry, no upgrade.
The second technique uses a crude but effective hack, replacing the compatibility appraiser module (Appraiserres.dll) with a zero-byte file of the same name. The popular Rufus utility performs this modification automatically with the click of a checkbox, and it works even on PCs that lack a TPM and are incapable of enabling Secure Boot.
