By Emily / Last Updated September 29, 2022

Need to convert MBR to GPT without data loss


Has anyone attempted to convert a drive from MBR to GPT? I have run into the drive size limit on a MBR: my 4TB hard drive only shows 2TB, and the rest space shows unallocated space, which cannot be used at all. I was told that i need to convert the disk to GPT, another partition scheme, but how? Will that damage my data? If so, how to avoid that? Thanks!

Nowadays, many Windows users search for a satisfactory answer to "how to convert MBR to GPT without losing data" in various technical blogs and forums. Microsoft has already officially announced that directly upgrading from Windows 10 to Windows 11 system will require the UEFI and GPT, which makes the requirement of the conversion of MBR to GPT surge. The difference between MBR and GPT and personal situations offer a reasonable explanation about why people need to convert MBR to GPT without data loss.


▶The MBR hard disk can only support a 2TB hard disk at most, but GPT can support 256TB.

▶The users can only create 4 primary partitions or 3 primary partitions and 1 extended partition on an MBR disk at most. The GPT can support 128 primary partitions at most.

▶Some booting mainboards cannot support MBR as their system drive, such as MAC.

Many users look for a way to convert MBR to GPT during or after Windows installation and they cannot delete all partitions for conversion. Will converting MBR hard disk to GPT delete data? The answer varies depending on which way you choose. Some methods do require you to delete the existing partition (of course, along with the inside data) before MBR to GPT conversion, yet not all the methods are.

Best way to convert MBR to GPT without data loss in Windows

It is well-known that Windows built-in Command Prompt and Disk Management can convert MBR to GPT only when you delete all partitions on the target disk; of course, you will lose all data inside as well. Moreover, they cannot convert system disk between MBR and GPT under the Windows environment since you are not allowed to delete system partition within Windows. 

So is there a way to convert data disk or boot disk from MBR to GPT without losing data? Of course, YES! The best method should be employing a third-party MBR to GPT converter like AOMEI Partition Assistant Professional. It can help you easily convert both system disk and data disk from MBR to GPT within Windows as long as the OS can boot up successfully. Besides, it does not require you to delete partitions beforehand, so all your data will be safe. It works on all Windows PCs: Windows 10, Windows 7, Windows 8/XP/Vista, and the newest Windows 11 operating system. You may want to download its Demo edition to have a try first.

Try Pro Demo Win 11/10/8.1/8/7/XP
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If you plan to convert the MBR system disk to GPT, please ensure the motherboard supports EFI/UEFI boot mode, otherwise, the system cannot boot successfully after conversion.
It is suggested to backup important data before you start since data loss might be caused by inappropriate operations or other unexpected errors.
If you’re running Windows 10 v1703 and higher, you may turn to Windows 10 MBR2GPT convert tool to convert the system disk from MBR to GPT style.

Step 1. Install and launch the software, right-click the MBR disk you want to change, and then choose Convert to GPT Disk.

Convert Data Disk to GPT

Step 2. In the pop-up windows, click OK to continue.

OK to GPT Data Disk

Step 3. Click Apply to operate, and then your disk will be changed into GPT disk style.

Apply to GPT Data Disk

With the help of the AOMEI Partition Assistant, it is quite easy to change a disk from MBR to GPT, or GPT to MBR without losing any data. To convert MBR to GPT without losing data on Server 2012/2016/2019, you need to turn to the Server Edition, which designs for both Server and Windows OS.

Another 2 methods to convert MBR disk to GPT on Windows

The previous content is about how to convert MBR to GPT without losing data using a 3rd-party tool. Next, we will also show you how to convert MBR to GPT using Windows built-in utilities: Diskpart in CMD and Disk Management. However, please note these 2 methods require deleting all existing partitions in the target disk first. They are recommended to convert non-system disks that contain less important data. To convert a disk with partitions onto MBR or GPT without losing data, you need to back up the required files in advance. And then check out the following detailed tutorial.

1. Use Diskpart to convert MBR disk to GPT

As one of the Windows built-in tools, Diskpart is a common choice for users to convert disk or format disk partition. The Diskpart Command can help convert MBR to GPT by the following steps.

Step 1. Press Windows key + R key simultaneously, and input "diskpart" in the box. Press Enter.

Step 2. Input "list disk" to list all disks connected to your computer.

Step 3. Input "select disk n" (n is the number of MBR disk) to select the MBR disk you want to convert to GPT.

Step 4. Input "clean" to delete all partitions existing on the target disk.

Step 5. Input "convert gpt".

Convert Gpt Cmd Windows 10

Note: to use Command Prompt to convert system disk to MBR or GPT, you need to boot the computer from the Windows installation media, press Shift+F10 at the Windows Setup screen to bring out Command Prompt window, and then run the above commands to convert the boot disk.

2. Use Disk Management to Convert MBR to GPT

You can enter Disk Management by right-clicking My Computer > Manage > Disk Management and using it to convert MBR to GPT. But same as Diskpart, it does not permit you to convert any MBR disk with partitions on it. So you have to delete partitions first, otherwise, you will find Convert to GPT Disk is grayed out.

Convert to GPT Grayed Out

Final Words

From the content above, it is easy to conclude that AOMEI Partition Assistant can convert MBR to GPT, or convert GPT to MBR without losing data. But in Diskpart and Disk Management, removing partitions/volumes is an inevitable step of the conversion. So AOMEI Partition Assistant offers the best way to convert MBR to GPT without data loss in Windows 7, 8, 10, and 11. MBR and GPT have different merits and shortcomings under different situations. Just choose the right one based on your situation.