CentOS

Hi,

I have installed CentOS using VMWare Workstation with Firmware type UEFI, Now if I try to convert the main partition from GPT to MBR it does not allow, It says New Protective MBR
So does this mean that if I have installed as UEFI then I cannot change to MBR ?

The legacy boot starts by loading and executing (first stage of) bootloader from the first sector of the drive.

The UEFI boot starts by looking for ESP (EFI System Partition, fat32) from the GPT (GUID Partition Table)
and then bootloader (an *.efi executable) from ESP. The bootloader is loaded and executed.

That is, the UEFI knows how and does read GPT.

The data of partition table of MBR is also in the first sector of the drive.
The data of partition table of GPT is elsewhere on the drive.

The GPT can write a "fake table" in MBR format. It typically has one partition that covers all the sectors allocated to "real" (GPT) partitions.
The purpose of the "Protective MBR" is to show to programs that can read only MBR that sectors of the drive are actually in use.
Otherwise such programs would assume "no partition table, all unallocated, free to overwrite".


Why would you want to convert partition table format?

Just to practise and see how it works
As soon as I tried to convert GPT to MBR which ultimately did not convert and last when I rebooted the system is not working that's the reason I asked as to is it that if one has formated using GPT, can it be converted to MBR and vice-a-versa.