"Secure boot can be enabled when the system is in user mode" means that Secure Boot functions when the system firmware is configured to User Mode rather than Setup Mode.
Explanation of Secure Boot User Mode
- Secure Boot User Mode is a state where Secure Boot is fully activated and the firmware enforces signature verification for boot loaders and EFI binaries.
- In this mode, only signed boot components that match the enrolled keys (Platform Key, Key Exchange Key, and signature databases) are allowed to boot.
- Keys cannot be modified or enrolled without authorization from higher-level keys.
- This prevents unauthorized or malicious software from loading during the boot process.
How to Solve Related Issues
- If Secure Boot cannot be enabled because the system is still in Setup Mode, it must be switched to User Mode by enrolling Secure Boot keys.
- The process involves booting into the UEFI/BIOS firmware settings, disabling Compatibility Support Module (CSM), and enabling Secure Boot.
- Then, enroll the Platform Key (PK) and other Secure Boot keys to transition the system into User Mode.
- On Windows, use advanced startup options to access UEFI firmware settings.
- Sometimes corrupted boot configuration data (BCD) or incompatible BIOS settings may block this transition.
- Ensure your system's firmware supports Secure Boot and is up to date.
- If CSM (Compatibility Support Module) is enabled, disable it as Secure Boot requires UEFI mode.
- Sign EFI binaries and bootloaders if using custom keys.
Common Causes for Secure Boot Not Enabling
- System still in Setup Mode (keys not enrolled)
- CSM enabled (not pure UEFI)
- Corrupt or incompatible boot entries or BCD
- Unsupported or outdated firmware
- Improper UEFI settings or key management
Summary
Secure Boot requires the system to be in User Mode to be enabled and effective. This mode is achieved by enrolling Secure Boot keys in UEFI firmware after disabling CSM and setting Secure Boot options appropriately. If issues occur, they can often be resolved by fixing UEFI settings, updating firmware, and ensuring the system is in pure UEFI mode with Secure Boot keys enrolled. This explanation aligns with the latest details from sources including Microsoft and motherboard UEFI documentation.
