Fix Secure Boot Violation Invalid Signature Detected

If you see a “Secure Boot Violation: Invalid signature detected” error on Windows, your PC is refusing to boot because it can’t verify the digital signature of the bootloader or drivers. This guide walks you through the most common fixes, from disabling Secure Boot temporarily to resetting your BIOS settings and repairing the boot configuration.

What You’ll Need

• Access to your BIOS/UEFI firmware settings (usually by pressing Del, F2, F10, or Esc during startup).
• A Windows installation USB drive (for repair options) — optional but recommended if the problem persists.
• Another working computer to create the USB drive if needed.

Step-by-Step

1. Restart your PC and enter BIOS/UEFI. As soon as the manufacturer logo appears, press the key shown on screen (often Del, F2, F10, or Esc). If Windows starts loading, you missed it — restart and try again.
2. Locate the Secure Boot setting. The exact path varies by manufacturer. Look for tabs like “Security,” “Boot,” or “Authentication.” On some systems it’s under “Advanced” or “UEFI Settings.”
3. Disable Secure Boot temporarily. Change the setting to “Disabled” or “Off.” If you see options like “Windows UEFI mode” vs “Other OS,” choose “Other OS” or “Disabled.” Save changes and exit (usually F10).
4. Boot into Windows. If Windows loads, the error is likely caused by a corrupted bootloader or a driver that isn’t properly signed. You can now try the fixes below, then re-enable Secure Boot later.
5. If disabling Secure Boot doesn’t help, reset BIOS to defaults. In BIOS, look for “Load Defaults,” “Load Optimized Defaults,” or “Reset to Factory Settings.” Save and exit. This clears any misconfigured boot settings.
6. Check boot order. Ensure your main hard drive/SSD is first in the boot priority list. Sometimes a USB drive or another disk with an invalid signature is being tried first.
7. Run Windows Startup Repair. If you still can’t boot, insert your Windows installation USB, boot from it, and select “Repair your computer” > “Troubleshoot” > “Advanced options” > “Startup Repair.” Follow the prompts.
8. Use Command Prompt to rebuild the BCD. From the same Advanced options, open Command Prompt and run these commands one by one, pressing Enter after each:
   bootrec /fixmbr
bootrec /fixboot
bootrec /scanos
bootrec /rebuildbcd
   Then type exit and restart.
9. Re-enable Secure Boot. Once Windows boots normally, go back into BIOS and re-enable Secure Boot. If the error returns, you may need to update your motherboard firmware or check for driver issues.

Common Mistakes

• Disabling Secure Boot permanently without finding the root cause. This leaves your system less secure and may cause issues with Windows updates or newer games that require it.
• Not saving BIOS changes. Forgetting to press F10 (or your save key) means your changes don’t apply.
• Assuming the error is always a hardware issue. Often it’s a software or configuration problem that can be fixed without replacing parts.
• Using a Windows installation USB that’s corrupted or outdated. Make sure the USB is created with the Media Creation Tool and is for the same version of Windows (e.g., Windows 11).

Tips

• Update your BIOS/UEFI firmware. Manufacturers regularly release updates that improve Secure Boot compatibility. Check your motherboard or PC manufacturer’s website for the latest version.
• Clear CMOS if you can’t access BIOS. If your PC loops on the error and won’t let you into BIOS, unplug the power, remove the small round battery on the motherboard for 30 seconds, then put it back and power on. This resets BIOS to defaults.
• Check for recently added hardware. A new graphics card, SSD, or other device with an unsigned option ROM can trigger this. Remove it and see if the error goes away.
• Use Windows’ built-in System File Checker. After booting, open Command Prompt as administrator and run sfc /scannow to repair corrupted system files.

Troubleshooting

• If you can’t even get into BIOS: Try pressing the key repeatedly as soon as the PC powers on. If that fails, unplug all peripherals except keyboard and monitor, then try again. If still stuck, clear CMOS as described above.
• If disabling Secure Boot doesn’t help: The issue might be a corrupted bootloader. Boot from the Windows USB and try the bootrec commands. If they fail, you may need to perform a “Startup Repair” or reset this PC (keep files) from the recovery environment.
• If the error appears after a Windows update: Try uninstalling the latest update from the recovery environment (Advanced options > Uninstall Updates).
• If you have a dual-boot setup: The other OS may have overwritten the bootloader. Reinstall GRUB (for Linux) or use EasyBCD to restore the Windows boot manager.
• If the error only happens occasionally: It could be a failing hard drive or SSD. Run a disk check (chkdsk) and check SMART status in BIOS or with a tool like CrystalDiskInfo.

Frequently Asked Questions

What exactly causes the “Invalid signature detected” error?

Secure Boot checks that the bootloader and critical drivers have a valid digital signature from Microsoft or your PC manufacturer. If the signature is missing, corrupted, or the bootloader has been modified (e.g., by malware or a failed update), the PC refuses to boot.

Is it safe to disable Secure Boot?

Yes, temporarily. It reduces protection against bootkits, but for most home users the risk is low if you’re careful about what you download. Re-enable it after fixing the issue.

Will I lose my files if I run Startup Repair?

No, Startup Repair only fixes boot files and doesn’t touch personal data. However, it’s always wise to have a backup.

Can a BIOS update fix this error?

Yes, if the error is due to a firmware bug or compatibility issue with new hardware or Windows updates. Check your manufacturer’s support page.

Why does the error appear after I installed Linux?

Linux installers often replace the Windows bootloader with GRUB, which may not have a valid Secure Boot signature. You can either disable Secure Boot or install the signed shim bootloader.

What if I don’t have a Windows installation USB?

You can create one on another computer using Microsoft’s Media Creation Tool. Alternatively, you can try resetting BIOS and checking boot order first — sometimes that’s enough.

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