By Ivy / Last Updated June 11, 2020

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Overview of partition style
Why change partition style of your hard drive?
Two methods to change partition style in Windows 10/8/7

Overview of partition style

Before realize why and how to change partition style, let's have a basic understanding of partition style. In general, partition style is referred to master boot record(MBR) and GUID Partition table (GPT). MBR uses 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.

This table demonstrates some of the differences between MBR and GPT:

Why change partition style of your hard drive?

Reasons for you to change partition style to GPT:

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

2. Make full use of disk that has large capacity. 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.

3. Get the error message: Windows cannot be installed to this disk. The selected disk has an MBR partition table. On EFI systems, windows……. when installing Windows.

Reasons for you to change partition style to MBR:

1. 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.

2. Receive this message “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.

Two methods to change partition style in Windows 10/8/7

Here demonstrates you two free tools to change a disk’s partition style in Windows 10/8/7. You can select your preferred one.

Change partition style via Diskpart

Diskpart, a Windows built-in tool, can help you to manage disk and partitions. Press Windows + R, input diskpart and click OK to run Diskpart. And then run the following steps to change partition style of your hard drive to MBR or GPT:

  • list disk

  • select disk

  • clean

  • convert gpt

Notes:

  • To convert a disk to MBR, replace “convert gpt” with “convert mbr”

  • The command “clean” will delete all volumes and data on the selected disk. Thus, you’d better back up important data at the beginning.

Convert partition style via third party partition manager

If your disk is not empty and you don’t want to delete volumes on it, you can turn to a third-party partition manager, AOMEI Partition Assistant Standard. It enables you to convert partition style of a disk to GPT or MBR without deleting any partitions. Free download it and take a closer look at how it works:

Step 1. Install and launch the software. Right-click the disk whose partition style needs to be changed to GPT and choose “Convert to GPT Disk”.

Convert Disk 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

Gpt Ok

Step 3. Now, you can preview the result. In this window, you already can see the disk you select to convert, just click "Apply" and “Proceed” to commit it.

Gpt Apply

Notices:
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.
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.
AOMEI Partition Assistant Standard supports you to convert non-system disk between MBR and GPT without losing data. If you want to change partition style of system disk, you can employ AOMEI Partition Assistant Professional.