There are two types of BIOS: Legacy BIOS and UEFI BIOS.
There are two types of partitions: MBR Partition and GPT Partition.
If the system partition is an MBR partition, the BIOS can be a Legacy BIOS or UEFI BIOS.
If the system partition is a GPT partition, the BIOS has to be a UEFI BIOS.
The system partition appears to be a GPT partition in this system, but the BIOS is a Legacy BIOS.
Safecode Defencecure setup detects the mismatch in the BIOS and system partition and prompts the error message.
To fix the problem, you need to either change the BIOS setting to UEFI or revert the system partition to the MBR partition.