By Emily / Last Updated March 30, 2020

Reasons to convert MBR to GPT

MBR and GPT are two different standards to define the layout of the partition table on the hard disk. And it is commonly acknowledged that GPT (GUID Partition Table) is better than MBR (Master Boot Record). Compared with MBR, GPT has several advantages as below:

GPT supports disk larger than 2TB whereas MBR supports up to 2TB hard disk.

GPT allows you to create 128 primary partitions while MBR allows you to create 4 primary partitions at most.

Different from MBR, GPT stores the partitioning and boot information in multiple locations so that you can easily recover them when it is corrupted.

Those above advantages are the main reasons for which some users want to convert MBR to GPT.

How to convert MBR to GPT via CMD Prompts in Windows 10/8/7?

To change disk from MBR to GPT in Windows 10/8/7, CMD command line is a great tool you can make use of. As for how to finish MBR to GPT conversion through it, refer to the steps below:

This method requires you to delete all partitions on the selected disk, so please backup all the data in advance.
The CMD only works on converting data disk and external hard drive to GPT since the system related partitions cannot be deleted within Windows.

Step 1. Open an elevated Command Prompt: press Win+R on your keyboard to open Run dialogue, in which type cmd and hit on Enter.

Step 2. In the elevated Command Prompt window, type diskpart and press Enter to launch DiskPart Windows. And execute following commands in sequence.

  • list disk (display all the online disks)

  • select disk n (n represents the number of the target MBR disk)

  • clean (remove all partitions on the target disk if there are)

  • convert gpt


After the conversion is finished successfully, type "Exit" and press Enter to leave this window.

Convert MBR to GPT without data loss with CMD alternative

From the above, we know it is necessary to backup MBR disk before you convert MBR to GPT via CMD to avoid losing important data. Moreover, that method can only convert data disk from MBR to GPT. So you might wonder whether it is possible to convert data and system MBR disk to GPT without deleting partitions and data loss.

Luckily, it is possible with the help of AOMEI Partition Assistant Professional. This software can convert both data and boot disk from MBR to GPT without removing any partitions and data loss.

Supported OS: Windows 10, Windows 8, Windows 7 and Windows XP/Vista (32-bit and 64-bit)

Step 1. Install and run AOMEI Partition Assistant. Right-click the disk you want to convert to GPT and select “Convert to GPT Disk”.

Convert 3tb Mbr Disk To Gpt

Step 2. Confirm your operation by clicking “OK” to continue.

Ok 3tb Disk

Step 3. Click “Apply” button on the toolbar to commit the pending operation.

Apply 3tb

Further reading: convert MBR to GPT via CMD during OS installation

If you meet the error "Windows cannot be installed to this disk. The selected disk has an MBR partition table. On EFI system, Windows can only be installed to GPT disks" during the Windows installation process on your PC, you may be eager to know how to convert MBR to GPT via CMD during installation.

Below we will take how to change disk from MBR to GPT in Command Prompt when you install Windows 10.

Converting system disk to GPT using CMD will wipe all data on the system disk.
Before converting boot disk from MBR to GPT, you need to ensure your motherboard supports UEFI boot mode since you have to change boot mode from Legacy BIOS to UEFI after conversion.

Step 1. Boot your computer from the Windows installation CD/DVD.

Step 2. Wait for the "Windows Setup" screen.

Windows 10 Setup

Step 3. Press “Shift + F10” keys together on the keyboard to open the command prompt window.

Step 4. Type “Diskpart” into the CMD window.

Finally, execute the commands “list disk->select disk #->clean ->convert gpt” to convert the disk from MBR to GPT.

If you are not able to boot from DVD media, that is, your PC does not have an optical drive, you can turn to AOMEI Partition Assistant Professional as well, with which you can create a bootable flash drive and convert MBR to GPT without booting into Windows or deleting existing volumes/data.

Note: An empty USB drive is required and you need to connect it to a working Windows computer.

Step 1. Install and launch AOMEI Partition Assistant Professional on the working PC. Click “Make Bootable Media” in the left Wizard list and follow the wizard to create a bootable USB drive.

Make Bootable Media

Step 2. Plug the created bootable USB drive into the computer whose OS installation process is interrupted by the MBR to GPT conversion issue, change the boot priority to the USB drive and boot your PC from it.

Step 3. Once login, you will enter the main interface of AOMEI Partition Assistant Professional. Right click the system disk and select “Convert To GPT Disk”.

Convert System Disk To Gpt

The rest steps are similar to the above part on converting data disk to GPT.

Wrapping things up

Above is all about how to convert MBR to GPT via CMD and using AOMEI Partition Assistant. Obviously, AOMEI Partition Assistant is a much wiser choice if you want to convert MBR disk to GPT without deleting existing partitions or losing data on the MBR disk.

If you are running Windows Server operating system, you can try AOMEI Partition Assistant Server, which owns all features of Professional edition such as migrate OS to SSD/HDD, copying MBR disk to GPT disk, or GPT disk to MBR, etc, convert dynamic disk to basic without removing volumes, and more compatible (both Server and Windows PC are supported).