Convert Disk between MBR and GPT in Windows 10 without Data Loss

MBR and GPT are different disk partition styles. MBR is short for Master Boot Record, whose maximum size of disk is 2TB. And only allows you to create 4 primary partitions or 3 primary partitions plus 1 extended partition. If you want to create many partitions on MBR disk, the number of primary partition should be no more than three and plus one extended partitions, then you can make logical partitions on extended partition.

GPT, short for GUID Partition Table, has not the limitation on the number of partition and the size of disk. But as for GPT, you should know that system installed on GPT disk can only be booted from UEFI (United Extensive Firmware Interface). Besides, removable media cannot be converted to GPT.

To check if your Windows 10 disk is MBR or GPT, please refer to difference between MBR and GPT.

It is clear from what I mentioned above. However, the question arises - should you use MBR or GPT in Windows 10? MBR can only support up to 2TB disk. What does this really mean? For instance, if you have a MBR disk whose size is 3TB, the rest of 1TB will be showed as unallocated space in your Windows 10, but you can't use it. Therefore, in order to make full use of storage space, most of users will choose to convert MBR to GPT.

However, some operating systems such as Windows XP 32-bit, Windows 2003 32-bit, Windows 2000, Windows NT4 don't support GPT disk. In these operating systems, GPT disk will be shown as GPT protective, and you are not allowed to access data in the disk unless you convert GPT to MBR.

Every coin has two sides, just like MBR and GPT. So among the large number of Windows 10 users, they need to convert MBR to GPT disk or convert GPT to MBR disk depending on their own requirements.

Usually, there are 2 common ways for Windows 10 users to make conversion between MBR and GPT disks. The following will show you the details.

Method 1: Windows 10 Disk Management

Disk Management Windows 10 is a built-in tool which allows you to create, delete, format, extend, and shrink partitions, convert to GPT or MBR, etc. To use this tool, you should open it by right clicking This PC<Manage<Disk Management. And then right click the disk you want to convert (here take Disk 0 for example). In the pop-up menu, you can find Convert to GPT disk unavailable. With this tool, you can only convert to GPT or MBR when there are no partitions on disk. so you must delete all the partitions on Disk 0 and then you can convert MBR to GPT.

Method 2: DiskPart Command Line

Windows 10 DiskPart is also a built-in tool command-line utility, it also can help you manage partitions and do conversion between MBR and GPT. As well as Disk Management tool, DiskPart only enables you to convert GPT to MBR or convert GPT to MBR when there are no partitions on the disk. If you satisfy the precondition, you can do as follows:
Step 1: Click "Start Menu" > 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". n is the number of the disk you want to convert. (take "Disk 1" for example)
Step 4: Input "clean" and press "Enter" to delete all partitions or volumes on the selected disk.
Step 5: Input "convert mbr" and press "Enter" to complete the conversion from GPT to MBR format.

The two methods mentioned above are able to convert MBR disk to GPT or GPT disk to MBR. But both of the methods will need you to delete all the partitions on disk at first. So before you do, you should backup all the data you may delete and then restore them. It seems you are in the risk of data loss. If the disk you need to convert is empty, you can use one of the methods above. Is there any way to convert disk between MBR and GPT in Windows 10 without data loss?

AOMEI Partition Assistant Professional is a powerful software for partition management. It allows users to convert MBR to GPT or convert GPT to MBR without deleting partitions and losing data. Besides this feature, it enables you to resize partition, merge partitions, make bootable CD, allocated free space, migrate OS to SSD, and more useful features. If you only need to convert Data disk between MBR and GPT styles, please download FREE partition manager - AOMEI Partition Assistant Standard. To convert System/Boot disk, you must use AOMEI Partition Assistant Professional.

Before you do:

  • If you want to convert system disk between MBR and GPT styles, please change boot mode between UEFI and Legacy. After conversion, GPT system disk can start Windows 10 from UEFI boot mode.
  • If there are more than 4 partitions on GPT disk, you cannot convert GPT to MBR disk unless you delete some unused partitions and limit the primary partition number within four due to the limitation of MBR disk.

1. Convert GPT to MBR Disk

Step1: Download this software, install and launch it. Right click the Windows 10 GPT disk you want to convert (here is Disk 2) and then choose Convert to MBR Disk.

Step2: Click OK to continue.

Step3: Click Apply to perform all the operations.

2. Convert MBR to GPT

Download, install and launch AOMEI Partition Assistant. Choose the Windows 10 MBR disk you need to convert and choose Convert to GPT Disk. And then do as the prompt like the steps of converting GPT to MBR.

Note: To guarantee PC bootable after the system/boot disk has been converted from MBR to GPT, you will need to enter into UEFI firmware settings, and switch from Legacy BIOS to UEFI mode. You may need to check your PC's or motherboard's manual for its specific instructions on how to change this setting.

To convert GPT disk to MBR or convert MBR disk to GPT during Windows 10 installation, you need to create a Windows PE bootable media on another computer, and then start up your computer from the bootable media to make the conversion.