Using 3 TB capacity Disk on an MBR with two partitions

using 3 tb capacity disk on mbr with.

"I face such a problem. I use 3 TB capacity in MBR, but actually, the capacity I can use is only 2 TB. Now, I want to keep the MBR partition style unchanged, but also want to use another 1 TB of capacity and create a new partition with unallocated space. MBR 3 TB can not create two partitions? if I want to use 3 TB capacity on an MBR with two partitions, is there a way to help me achieve this goal?"

If you want to take full advantage of a 3TB or 4TB MBR hard drive, you need to convert the MBR partition style to GPT. Because MBR only supports a maximum partition size of 2 TB, and only four primary partitions can be created, GPT disks can support creating more partitions with a larger capacity without practical limitations. Therefore, a 3 TB/4 TB MBR cannot create two partitions, but the MBR cannot create partitions larger than 2 TB.

So, what exactly are MBR and GPT? MBR (Master Boot Record) and GPT (GUID Partition Table) are two partition tables commonly used in Windows systems. A partition table is a table used to describe partitions on an HDD or SSD and help the drive find files so that the operating system can read data on the drive.

But the difference is that MBR needs to use BIOS to boot, whereas GPT needs to use UEFI to boot. GPT has more advantages than MBR. Because GPT disks are stronger and higher in terms of security. Quite specific differences can be seen in the following image:

Convert a 4TB/3TB drive to GPT with Diskpart (data loss)

Diskpart can convert MBR to GPT with multiple command lines. Here are the detailed steps.


  • 1. This method needs to clean your disk before converting, so if it is not a new hard drive or has important data on it, you should back up the disk first.
  • 2. In general, MBR and BIOS (MBR+BIOS), GPT, and UEFI (GPT+UEFI) complement each other. When converting a system disk to a GPT disk, make sure your computer's motherboard supports UEFI boot mode.

Step 1. Press "WIN+R", type "CMD" and press Enter to open a Command Prompt. Then, enter "diskpart" and press Enter.

Step 2. Type the following command, remember to press Enter after you enter each one.

  • list disk
  • select disk 1 (number means drive letter, replace with your 4 TB drive letter)
  • clean (delete all partitions on selected disk)
  • convert gpt

When "DiskPart successfully converts the selected disk to GPT format" appears on the screen, type "exit" and press "Enter" to exit the program. Currently, your partition style has been changed from MBR to GPT and its capacity has been extended.

Hopefully, this article about Using 3 TB capacity Disk on an MBR with two partitions, gives you a little insight. Also, read an article about Using the Toolkit on macOS 10.15 Catalina that you may need to know. Thank you.

Previous Post Next Post