GPT protective partitions are a defense mechanism that springs into action to prevent users accessing certain partitions, but ...

you will need to have a GPT partition-style disk. But, if the MBR partition is there, then you have to convert the MBR partition to GPT first. To do this, you can use the built-in DISKPART utility.

Convert MBR to GPT using the Recovery Environment ... privileges and use commands like “mbr2gpt” to convert your disk to GPT. Restart your system and access the BIOS settings.

If your disk is using the GPT partitioning scheme ... The other, more likely solution is to convert your disk to use the old ...