Windows 11 Hyper V won't boot official ms install media when secure boot is enabled

In Hyper‑V this is almost always caused by the Secure Boot template being set to the wrong authority for the guest.

Fix (most common)​

1) Shut down the VM.
2) Hyper‑V Manager → right‑click VM → Settings → Security
3) Make sure Enable Secure Boot is checked
4) Set Template to Microsoft Windows (not “Microsoft UEFI Certificate Authority”)
5) Start the VM and boot from the ISO again.

• “Microsoft Windows” = for Windows 10/11/Server ISOs
• “Microsoft UEFI Certificate Authority” = typically for Linux/other bootloaders, and it can trigger Secure Boot violations with Windows media.

Also verify these two quick things​

• The VM is Generation 2 (Secure Boot only applies to Gen 2).
• The ISO you mounted is the x64 Windows 11 ISO (not ARM64). An ARM64 ISO won’t boot in a normal x64 Hyper‑V VM.

If it still won’t boot​

Tell me what you see when it fails (exact text). If it’s a blue/black screen that says “Secure Boot Violation” or similar, a screenshot of that screen will pinpoint it.