Secure Boot Violation

[Xhrilla]

I'm experiencing a Secure Boot issue on my HP desktop. I've tried numerous troubleshooting steps and researched multiple solutions, but I haven't been able to resolve it.

The computer will only boot into Windows when Secure Boot is disabled. If I enable Secure Boot, the system either displays a "Secure Boot Violation" error or "Boot Device Not Found (3F0)" and won't boot into Windows.

While searching for solutions, I found that many HP systems require disabling Legacy Boot or ensuring the system is in UEFI mode. However, my BIOS does not have a Legacy Boot option, so I'm unable to follow those instructions.

I've already tried several troubleshooting methods without success. I'd like to know

What could be causing Secure Boot to reject Windows on my system?

Are there any HP-specific steps for my model to restore Secure Boot functionality?
Any guidance would be appreciated, as I'd like to use Secure Boot without preventing Windows from booting.

[BeemerBiker]

Secure Boot issues on HP desktops (HP Device Manager / Thin clients)

Based on the provided information, the only Secure Boot–related guidance is for HP desktops/all‑in‑ones when you add an older PCIe x16 video card to a Windows 8–class HP PC that uses UEFI and Secure Boot.

If your issue started after installing an older graphics card, try disabling Secure Boot and enabling Legacy Support:

1. Enter BIOS/UEFI setup

   • Turn on (or restart) the HP desktop.
   • Immediately press the Esc key repeatedly until a Startup Menu appears.
   • Press the key for Computer Setup (BIOS), usually listed there (for example, F10).

2. Change Secure Boot settings

   • In BIOS, use the arrow keys to go to Security.
   • Select Secure Boot Configuration and press Enter.
   • When the red warning screen appears, press the indicated key (for example, F10) to continue.
   • Set Secure Boot to Disabled.
   • Set Legacy Support to Enabled.
   • Press F10 to accept / save the changes.

3. Save and confirm

   • Choose Save Changes and Exit.
   • When prompted, confirm (for example, select Yes).
   • On the next screen, you may be asked to type a numeric code to confirm the mode change; type the code shown and press Enter.

4. Boot into Windows and install drivers

   • Let the system boot into Windows with the new video card.
   • Install or update the appropriate graphics drivers (from the card vendor’s media or website).

If your Secure Boot problem is unrelated to installing an older graphics card or UEFI/Legacy changes, or if these steps don’t match what you’re seeing, I don't have that information available. Please try rephrasing your question or contact HP support for further assistance.

Spoiler

Expand spoiler for references

Upgrading Hardware on HP PCs - From the Desktop with Kevin and Randy

Sources

1. Upgrading Hardware on HP PCs - From the Desktop with Kevin and Randy