By AOMEI / Last Updated August 24, 2020

What is MBR?

At the end of the ROM BIOS bootstrap routine, the BIOS reads and executes the first physical sector of the first floppy or hard disk on the system. This first sector of the hard disk is called the master boot record (or sometimes the partition table or master boot block). There is a small program at the beginning of this sector of the hard disk. The partition information, or partition table, is stored at the end of this sector. This program uses the partition information to determine which partition is bootable (usually the first primary DOS partition) and attempts to boot from it.

Drawbacks of MBR disk

An MBR disk takes Master Boot Record as the partition table. It consists of a sequence of 512 bytes located at the first sector of a data storage device such as a hard disk. Due to the fact that the MBR is a quit old partition structure for Windows systems, it is kind of out-of-date and has some disadvantages, compared with the newer partition table GPT (GUID Partition Table):

● It is vulnerable to today's internet environment: Some viruses can exploit master boot codes that run automatically when the computer starts up. It can be easily corrupted once it gets affected.
● Master boot record (MBR) disks use the standard BIOS partition table, which is the legacy boot mode and kind of slow to boot up.
● MBR disks do not support more than 4 primary partitions on each disk. But you can create 3 primary partitions and multiple extended partitions.
● The MBR partition method is not recommended for disks larger than 2 terabytes. Some users reported that their 4TB hard drive only shows 2TB. It is probably because they use MBR partition table on a large hard drive.

Advantages of MBR disk

However, lots of people still are insisting on using the MBR partition table because of the good compatibility with some old operating systems, especially for those older than Windows 7. And a PC using BIOS boot mode, it is also recommending to take the MBR partition table.

Comparison Mbr And Gpt

If you need to change a disk from GPT to MBR partition style with Disk Management or Diskpart as long as the disk is empty and contains no volumes. Or you can turn to the AOMEI Dynamic Disk Manager, you can convert GPT to MBR or MBR to GPT without deleting data.


MBR is the traditional partition table format. Relying on its great compatibility, there are still lots of people who are using MBR disk. If you want to partition your hard drive, you can convert MBR disk to GPT. Because the GPT provides more advanced features.