How to convert MBR to GPT in Windows 10

by John, Published on: November 2, 2020

This article introduces how to convert MBR to GPT without losing data in Windows 10 with 2 freeware.

On a MBR disk you can only create maximum 2TB partition and use only 2TB disk space in most cases. In addition, you can only create maximum 4 Primary partitions on a MBR disk. Therefore, if you have a 2TB+ disk or want to create more than 4 Primary partitions, you must use GPT disk. If you selected MBR when initializing a hard disk or have saved files to a MBR disk in an OEM computer, you need to convert MBR to GPT.

There are 3 common ways to convert MBR disk to GPT in Windows 10 (32 & 64 bit). In this article, I'll show you all methods with detailed steps, select the one that fits for your needs.

1. Convert MBR to GPT in Windows 10 Disk Management

This method is only used if you can delete all partitions on the MBR disk.

The same with previous versions, Windows 10 has native Disk Management tool which has the option to convert MBR to GPT and convert GPT disk to MBR. However, there must be no partition on the disk. If there's even one partition, the option "Convert to GPT Disk" is grayed out when you right click this MBR disk.

After deleting all partitions on this disk, the convert option will be activated. Caution: remember to transfer files to other place before deleting. If you don't want to delete any partition, jump to the second method.

How to convert MBR to GPT in Windows 10 Disk Management:

  1. Press Windows and X hot-keys together and click Disk Management in the list.
  2. Right the partitions on this MBR disk and select Delete Volume one by one.
  3. Right click the front of this disk and select Convert to GPT Disk. In a short while, conversion will be completed.

Obviously, it's better to convert MBR to GPT without losing data for Windows 10 computers. Before starting, check the MBR disk that you want to convert is the system disk or a data only disk. The methods to convert these disks are different.

2. Convert MBR to GPT with Windows 10 MBR2GPT.exe

This method is used to convert system MBR disk to GPT (the disk with Operating System).

The strategy to manage files and the method to boot Windows are different on MBR and GPT disk. To convert disk from MBR to GPT, many things will be changed. You should pay more attention when converting system disk to GPT, because it is where Windows Operating System booting from. If the conversion failed, your computer cannot boot.

There are some tools that can help you convert system disk from MBR to GPT, but no tool can ensure 100% bootable after converting. In all previous versions, you have to back up everything and try to convert with third party software, but in Windows 10 there's a new native tool. Windows 10 has MBR2GPT.exe which runs via command prompt tool. It is very easy and fast to convert disk with MBR2GPT but your disk partition layout must meet the requirements. If it doesn't meet, you can modify disk partition.

Requirements to convert system disk with Windows 10 MBR2GPT cmd tool:

  1. All partitions on the MBR disk must be Primary. If there's Logical drive, follow the method to convert it to Primary.
  2. There should be no more than 3 Primary partitions on this disk. If there are four or more partitions, follow the method to move some partitions to another disk. You may either keep them there or move them back after converting to GPT disk.
  3. All partitions on this disk must be formatted with FAT16/32 or NTFS file system.

Some people received error "Disk layout validation failed for disk 0" while converting disk with MBR2GPT:

As I explained above, there's a Logical drive in the first screenshot, and there are 4 partitions on both screenshots.

MBR2GPT will validate the disk partition layout before converting, if the validation failed, the conversion will stop, so it won't do any damage to your disk. If it converts disk successfully, the changes cannot be undone. Remember, there's no Windows native tool that is able to convert GPT to MBR without losing data.

How to convert MBR to GPT in Windows 10 with MBR2GPT command:

  1. Back up your system with Windows native or third party software in case of your computer doesn't support booting from GPT disk.
  2. Press Windows and R hot-keys together, input cmd and press Enter.
  3. In the command prompt window, input mbr2gpt /disk:0 /convert /allowFullOS and press Enter to execute. If your system disk is not 0, replace it with the right number. You'll see the disk number in Disk Management.

If you want to read more about MBR2GPT, input mbr2gpt /? in the command window or visit official page.

Pay attention to EFI partition

On most of MBR system disk, there's a small System Reserved partition. After converting this disk to GPT with MBR2GPT, System Reserved partition will be removed and another small EFI partition will be created.

MBR2GPT will first try to shrink the System Reserved partition, if there's enough free space, EFI partition will be created behind this Reserved partition. If there's not enough free space, MBR2GPT will shrink the boot partition (C drive) instead, then EFI partition will be created behind C drive. The problem is that Windows Disk Management can't resize, move or do any other operations to EFI partition.

If you want to make EFI partition on the left of C drive, extend the System Reserved partition before converting. (Extending to 2GB is absolutely enough)

Convert without extending System Reserved partition:

Convert after extending System Reserved partition:

NIUBI Partition Editor can shrink, move and extend the EFI partition, so you may ignore the step to extend system reserved partition. However, if you care about the position of EFI partition, remember to extend before converting.

3. Convert disk with free MBR to GPT converter

This method is used to convert MBR disk to GPT without Operating System in it.

It only requires 3 clicks to convert MBR to GPT with NIUBI Partition Editor. It has free edition for Windows 10/8/7/Vista/XP home computer users. Besides converting MBR disk to GPT, NIUBI Partition Editor helps you convert NTFS to FAT32, convert partition between Primary and Logical without losing data. It also helps you shrink, move, extend and merge partitions to optimize disk space, clone disk/partition to migrate Operating system and data. Create, delete, format, hide, defrag, wipe partition, scan bad sectors, etc.

How to convert MBR to GPT in Windows 10/8/7/Vista/XP with NIUBI Partition Editor:

  1. Download and install, right click the front of the MBR disk and select "Convert to GPT Disk".
  2. Simply click Yes to confirm, a pending operation will be added on bottom left corner.
  3. Click Apply on top left to take effect, done.

Watch the video how to convert MBR disk to GPT in Windows 10:

Video guide