By Ivy / Last Updated June 20, 2017

Partition Style

In our life, many people always say that i want to change partition style from MBR to GPT or convert GPT to MBR without losing data. Now, We will continue to know more detail information about partition style first, and then begin to change it.

In general, partition style is referred to master boot record(MBR) and GUID Partition table(GPT). MBR use standard BIOS partition table while GPT uses unified extensible fireware interface. In MBR, there are only allowed four entries, and every entry only allows 16 byte. In GPT, the number and size of partition entries on GPT disk depend on the partition table header. At the same time, extensible fireware interface(EFI) requires the minimum of 16384 byte for the partition table. So a GPT disk has 128 entries and every entry has 128 byte.

Why Do You Need to Change Partition Style?

Change MBR to GPT:

1. You want to create more partition. In MBR, You are allowed to create four primary partitions at most or three primary partitions and one extend partition. However, in GPT, there is no limitation on the number of partition. You can create partition up to 128.

2. You want to own a large-capacity in your hard disk. In MBR, the capacity is less than 2 TB. In GPT, the capacity can reach up to 18 EB. It’s really obvious that if you need a large-capacity, GPT will be a better choice.

Change GPT to MBR:

Your computer does not have EFI fireware. If you want to boot your computer from a GPT hard disk, you must own an EFI fireware in advance. So if you don’t have an EFI fireware, changing GPT to MBR will be a nice choice.

Steps to Change Partition Style:

If you want to upgrade Legacy-BIOS to UEFI mode, you need to convert your hard drive from MBR to GPT. With this tool AOMEI Partition Assistant, you can change partition style without reinstalling Windows 10/8/7. Below is the guide:

Step 1: Download AOMEI Partition Assistant, install and launch it. Then enjoy it, you will see the main page. In this page, right click the disk you want to convert to GPT, then select Convert to GPT Disk.

Convert MBR to GPT

Step 2: There will be a prompt in a few seconds, click OK to ensure you want to convert the disk you selected to GPT disk.


Step 3: Now, you can preview result. In this window, you already can see the disk you select to convert, just click Apply to realize it.


Step 4: Below is the detail information about Convert MBR to GPT, click Proceed to continue this operation.


Notice: If your disk is being used by other programs, AOMEI Partition Assistant will give you three options. Retry is the recommended one, you can select this to close other operations and then execute this operation. Of course, you can select Restart Now to let this operation finish in PreOS mode.

Step 5: Finishing all above operations, you can just wait for a period of time. When this operation finish, click OK.


Up to now, you have already successfully changed MBR to GPT. Next, we will start to change GPT to MBR.

Step 1: Selecting one GPT disk you want to convert, then choose Convert to MBR Disk. A few seconds later, click OK in a prompt window.

Convert GPT to MBR

Step 2: Click Apply to convert the disk you select to MBR.

Apply 2

Step 3: Now, previewing the detail information about the newly MBR disk and click Proceed to continue this operation.

Proceed 2

Step 4: In this window, you can see the real operation. Just wait, and click OK when this task finish.

Finish 2

Now, all the process has been finished. Congratulation, you can successfully change partition style between MBR and GPT. But there still are some things you need to notice:

1. If you don’t want to lead boot failure, do not change the disk which saves windows OS to GPT disk. Because booting windows from MBR requires BIOS mode and booting from GPT needs UEFI mode. What’s more, the Windows 32 bit OS can not be installed on a GPT disk.

2. Users always receive this message like”The selected disk is of the GPT partition style”, when you boot your computer from a newly install hard disk. The simplest way is to convert GPT disk to MBR disk.