By AOMEI / Last Updated October 28, 2019

MBR and GPT are two different partition structures. MBR (short for Master Boot Record) allows for a maximum partition size of 2TBs with 4 primary partitions or 3 primary partitions and 1 extended partition. If you need to create a lot of partitions on an MBR disk, you should create (a maximum of) three primary partitions and then one extended partition which will allow you to create multiple sub-partitions.

GPT (short for GUID Partition Table) theoretically doesn’t have any limits on the number of partitions it can hold or the size of the disk that can be used. Disks that are formatted with a GPT partition table can only be booted from a UEFI (United Extensive Firmware Interface) enabled system. Only users that can enable UEFI, will be able to take advantage of GPTs ability to create an unlimited amount of partitions. One small drawback of the GPT structure is that it can’t be used on removable media (USB sticks, CDs, DVDs etc.).

Users often ask should you they use MBR or GPT structure in their Windows 10 PCs. MBR structures can only support disks up to 2TBs in size which means that if you have a drive larger than 3TBs, 1TB will show as unallocated space that you can use in Windows 10. Therefore, in order to take full advantage of the drives storage most users will choose to convert their drivers from MBR to GPT.

You should note that Windows XP 32-bit, Windows 2003 32-bit, Windows 2000, Windows NT4 operating systems can’t support GPT disks. When using these systems GPT disks will show ‘GPT Protective’ partitions and you won’t be able to access the data on the disk until you convert it from GPT to MBR.

As with everything, there are pros and cons to using GPT or MBR partition structures. The majority of today’s users will convert between the structures depending on the present situation and their hardware’s requirements.

Convert your disk between MBR and GPT in Windows 10 (with Data loss)

There are two ways common methods for Windows 10 users to convert their disks between MBR and GPT partition structures. Below we show you how you can do it:

Method 1: Windows 10 Disk Management

Windows 10 Disk Management is a built-in tool which allows you to create, delete, format, extend and shrink partitions, and convert between GPT or MBR structures. To use Disk Management, you need to open it by right clicking on This PC -> Manage -> Disk Management. Next, you should right click on the disk you want to convert (here we use Disk 0).

In the pop-up menu, you will find the Convert to GPT disk option unavailable. When using Disk Management, you will only be able to convert between GPT or MBR when there are no partitions on the disk. In order to do the conversion, you must first delete all the partitions on ‘Disk 0’ and then you will be able to begin the conversion process.


Method 2: DiskPart Command Line

DiskPart is a Windows 10 built-in tool which you can access through the command-line utility. It is able to help you manage your disk partitions and do conversions between MBR and GPT partition structures. Like with Disk Management, DiskPart only allows you to convert GPT partitions to MBR partitions (or vice versa) when there are no partitions on the disk.

If you have no partitions on the disk, you can do the following:

Step 1. Click on the ‘Start Menu’ and input ‘DiskPart’ in the search box and press ‘Enter’. Click ‘Yes’ to open command prompt.
Step 2. Input ‘list disk’ and press ‘Enter’.
Step 3. Input ‘select disk n’ and press ‘Enter’. (Note: n is the number of the disk you want to convert).
Step 4. Input ‘clean’ and press ‘Enter’ to delete all the partitions or volumes on the selected disk.
Step 5. Input ‘convert mbr’ and press ‘Enter’ to complete the conversion between GPT and MBR formats.

The above two methods allow you to convert an MBR disk to GPT (or vice versa), however, both methods require you to delete all of the disk partitions beforehand. Therefore, you should backup all of your important data before you begin if you don’t want to lose it.

The above methods might not be what all users are looking for as they have the ability to cause data loss unless you spend time backing up your data. Fortunately, we will explain the ways ways to convert your disks partition structure without having to delete the partitions.

AOMEI Partition Assistant Professional Edition is a powerful third-party partition manager. It has the ability to convert between MBR to GPT partition structures (or vice versa) without requiring users to delete their partitions or lose their data. Users can also use AOMEI Partition Assistant Professional Edition to resize partitions, merge partitions, make bootable USBs/CDs/DVDs, allocate free space to other partitions, and migrate your OS to an SSD (or any other hard disk).

If you only need to convert your hard disk between MBR and GPT partition structures, you can download AOMEI Partition Assistant Standard Edition a FREE specialist partition manager. If you want to convert a System/Boot disk, you must upgrade to AOMEI Partition Assistant Professional Edition with all its premium features.

Tips before you convert:

  • If you want to convert a system disk between MBR and GPT partition structures you will need to change the boot mode from Legacy to UEFI so that the system can recognize the GPT disk and boot Windows 10.

  • If there are more than 4 partitions on your GPT disk, you will not be able to convert to MBR structure unless you reduce the total number to 4 by deleting the additional ones.

Step 1: Download the specialist software from here, install it, and launch the program. In the main window, you should right click on the disk that you want to convert (here it’s Disk 2) and choose the ‘Convert to MBR Disk’ option.

Convert System Disk To MBR

Step 2. Click OK to continue.

Ok


Step 3: Click ‘Apply’ to perform the pending operations.

Apply


2. Convert MBR to GPT

Download, install, and launch AOMEI Partition Assistant. Choose the Windows 10 MBR disk you need to convert and select the ‘Convert to GPT Disk’ option. Next, you need to follow the steps to convert your disk from GPT to MBR.

Convert System Disk To GPT


Note: To guarantee that your PC will boot after the system/boot disk has been converted from MBR to GPT you will need to switch from Legacy BIOS to UEFI mode. You may need to check your PCs (or motherboards) manual in order to find the specific instructions on how to change the settings.

To convert your GPT disk to MBR (or vice versa) during the Windows 10 installation, you will need to first create a Windows PE bootable Media on a different computer. You should then load your computer from the bootable USB and follow the steps to start the conversion.