This error message usually appears during a PC startup or after installing a new GPU. It means your system's BIOS is looking for a Graphics Output Protocol (GOP) driver-which is required for modern "UEFI" booting-but can't find it.

As a result, the motherboard is automatically switching back to CSM (Compatibility Support Module), which is an older "Legacy" way of booting.

Why Is This Happening?

There are three primary reasons your system is triggering this fallback:

• Older Graphics Card: If your GPU was made before 2014 (e.g., NVIDIA GTX 600 series or older, or AMD HD 7000 series), it likely lacks a UEFI-compatible BIOS (vBIOS).
• Disabled UEFI Support: The graphics card might have a physical "BIOS Switch" on the side of the board that is currently set to "Legacy" instead of "UEFI."
• Integrated Graphics Conflict: If you are using a dedicated card but the motherboard is trying to initialize the CPU's integrated graphics (which might be disabled or incompatible), it may throw this error.

How to Fix It

1. Check for a Physical Switch

Many modern performance GPUs have a tiny toggle switch on the top edge of the PCB. Look for labels like "OC / Silent" or "UEFI / Legacy." Ensure it is set to the modern/UEFI position while the PC is powered off.

2. Update the GPU Firmware

If you have a card that should support UEFI (like a GTX 760 or 900 series) but isn't being recognized, the manufacturer might have released a DisplayPort or UEFI firmware update. You would need to boot into Windows (using CSM) and run the update tool from the manufacturer's website.

3. Clear CMOS

Sometimes the BIOS gets "stuck" in a logic loop.

1. Turn off the PC and unplug it.
2. Remove the silver coin-shaped battery (CR2032) from the motherboard.
3. Wait 30 seconds, put it back in, and restart.
4. Enter the BIOS (usually by tapping Del or F2) and manually set Boot Mode to UEFI.

4. Secure Boot Requirements

If you are trying to run Windows 11, you generally cannot stay in CSM mode because Windows 11 requires Secure Boot, which only works in UEFI mode. If your card is too old to support GOP, you may need a newer GPU to fully utilize modern OS features.

Are you trying to install a specific operating system like Windows 11, or did this just start happening after a hardware change? I can help you check if your specific GPU model is compatible.