Hey folks,
I've been banging my head against this whole "your device is not ready" thing for a couple hours now and I've managed to solve it. Here's what I did.
First off, I had to enable TPM as it seems many of us were caught out by this. I have an MSI B450 TOMAHAWK MAX and the steps to do so were as follows:
- Boot into BIOS (Press DEL upon boot)
- Switch to Advanced Mode (F7)
- Settings -> Security -> Trusted Computing and enable the option of "Security Device Support"
Then I was met with an error that "device health attestation isn't available". To get this available, I needed to convert my boot drive to be UEFI compatible. You can do this with the built in MBR2GPT.exe tool that windows provides. I followed this guide to get it done.
Then, I switched my boot mode to UEFI and now device health attestation is available and I'm good to go for Windows 11.
TL;DR - enable TPM and make sure you're booting in UEFI mode.
I hope this helps someone!