Have you ever seen the message “Secure Boot is not supported” when turning on your PC?
This error can be alarming, especially if it blocks your system from booting or appears after an update or hardware change. But don’t worry — in most cases, it can be resolved with a few careful steps.
In this article, we’ll walk you through what Secure Boot is, why this error appears, and how to fix it — even if you’re not tech-savvy.
What Is Secure Boot, and Why Does It Matter?
Secure Boot is a security feature found in modern UEFI firmware. It ensures that only trusted operating system software is loaded when your computer boots, preventing malware or unauthorized code from starting up.
To enable Secure Boot, your system must meet certain conditions. If not, you may see the “Secure Boot is not supported” message — especially after a BIOS reset, OS reinstall, or hardware upgrade.
First, Ask Yourself These Questions
- Did you recently change your hardware (SSD, motherboard, etc.)?
- Did you reinstall Windows or upgrade your OS?
- Was your BIOS or UEFI reset to factory settings?
Understanding what changed can help pinpoint the exact reason for the error.
Solution 1: Check Secure Boot in BIOS/UEFI
- Reboot your computer and press the key to enter BIOS/UEFI (often F2, Del, Esc, or F10).
- Navigate to the Boot or Security tab.
- Locate the option named Secure Boot.
- If it’s Disabled, change it to Enabled.
- If it’s grayed out, go to OS Type / OS Mode Selection and choose UEFI OS.
- Save and exit BIOS (look for “Save & Exit” or “Exit Saving Changes”).
Note: Secure Boot only works if Windows is installed in UEFI mode — not Legacy BIOS mode.
Solution 2: Load Platform Key (PK)
If you see errors related to missing keys or signatures, you may need to manually install the Platform Key (PK).
- In BIOS/UEFI, find the section named Key Management or PK Management.
- Select Install Default Keys or Restore Factory Keys.
This reloads the trusted boot signatures required for Secure Boot to work properly.
Solution 3: Disable CSM (Compatibility Support Module)
CSM allows legacy BIOS support, but it conflicts with Secure Boot. If CSM is enabled, Secure Boot will be unavailable.
- Go to the BIOS/UEFI settings.
- Look for CSM Support or Legacy Support.
- Set it to Disabled.
Caution: Some older hardware or OS versions may require CSM. If disabling it causes boot issues, revert the change.
Solution 4: Update Your BIOS/UEFI
Sometimes, outdated firmware doesn’t fully support Secure Boot or contains bugs. Visit your PC manufacturer’s support website and check for the latest BIOS version.
Many vendors offer Windows-based BIOS update tools, which are safer and easier than USB flash updates.
Final Option: Reinstall Windows in UEFI Mode
If your current Windows installation is using Legacy BIOS mode, Secure Boot cannot be enabled. A clean reinstallation in UEFI mode may be required.
Check your current BIOS Mode:
1. Press Windows + R, type msinfo32, and press Enter.
2. In the System Information window, find the line “BIOS Mode”.
– If it says UEFI, you’re fine.
– If it says Legacy, Secure Boot won’t work unless Windows is reinstalled in UEFI mode.
Summary Table
| Cause | Solution |
|---|---|
| Secure Boot disabled | Enable it in BIOS/UEFI |
| Platform Key missing | Load default keys in Key Management |
| CSM enabled | Disable CSM in BIOS |
| Windows in Legacy mode | Reinstall Windows in UEFI mode |
| Outdated BIOS | Update to latest version from manufacturer |
Extra Tip: Hidden Issues That Might Be Overlooked
- Boot order issues: Make sure UEFI boot devices (like SSD or Windows Boot Manager) are listed first.
- Motherboard compatibility: Very old motherboards (pre-2015) may not support Secure Boot at all.
- Wrong OS installation type: Windows installed with MBR instead of GPT can block Secure Boot.
These are often missed during troubleshooting, but correcting them can resolve persistent errors.
Final Thoughts
Secure Boot errors can be frustrating, but they rarely mean your PC is broken. Most of the time, it’s just a BIOS setting or OS mismatch that can be corrected with a bit of patience.
If you’re uncomfortable navigating BIOS or making system changes, consider asking a technician or using a remote support service.
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💡 Looking for more tips? Check out our full list of Windows Help Guides.
