Convert MBR disk to GPT on Windows [10, 8, 7]


This tutorial explains how convert an MBR disk to GPT with or without data loss.



Why convert MBR disk to GPT?

Converting a disk to GPT is useful in more than one way !

First, using the GPT partitioning table allows you tooverride the limitations now disabling MBR. The GPT format allows you to create up to 128 partitions (instead of 4) and to create partitions of up to 256 TB (instead of 2.2 TB).

And second, the GPT is indispensable if you want to install Windows 7, 8 or 10 and fashion UEFI : Windows in UEFI mode requires that a disk use the GPT partitioning table and no longer the traditional MBR.

To take advantage of all these possibilities, you will need convert your MBR disk to GPT.

That’s good, that’s the subject of this tutorial! ?

Introduction: Convert a disk to GPT

Until now, the main problem that arose when one wanted to convert MBR disk to GPT is that the disk had to be empty, without partitions. It was therefore impossible to perform the conversion without losing all data of the disc.

But that was before ! With Gptgen and more recently with Microsoft’s MBR2GPT, it is now possible to convert an MBR disk to GPT without data loss.

In this tutorial, I suggest 4 methods to convert your disk to GPT:

  • With MBR2GPT: without data loss.
  • With Gptgen: without data loss.
  • With DiskPart: with data loss.
  • With the Disk Management tool: with data loss.

If you choose a method without data loss, I recommend that you exercise caution and back up your data : copy them to an external medium or create a disc image (disc image = exact copy of a disc saved as an image file).

Finally, note that only the MBR2GPT tool can convert a system disk in use.

Method # 1: with MBR2GPT

i Note : MBR2GPT is only available on Windows 10 v1703 and later versions of Windows 10.

MBR2GPT is a new tool developed by Microsoft that allows you to convert system disks (disks on which Windows is installed) MBR in GPT. It is not possible to convert data discs with this tool.

It is the only tool that can convert system disk in use. In other words, you can use it to convert the disk that Windows 10 booted from and from that same Windows 10.

To know how to use MBR2GPT, follow this guide:

MBR2GPT: Convert MBR disk to GPT without data loss

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Method # 2: with DiskPart

! Attention : all data on the disk will be erased.

Here is how to convert MBR disk to GPT with DiskPart :

  1. Open a Command Prompt. To convert your system drive, open this command prompt from Advanced Reboot Options or a Windows installation USB stick / DVD.
  2. Start DiskPart:
  3. Identify the number disk to convert to GPT:
    list disk
  4. Select the disk to convert to GPT (replace 0 by the number of your disc):
    select disk 0
  5. Display the disc information (to be sure you are not mistaken):
    detail disk
  6. Erase all the contents of the disc:
  7. Convert the disk in GPT:
    convert gpt
  8. Exit DiskPart:
  9. If you converted your disk to install Windows on it, you can continue by following this tutorial: install Windows 7, 8 or 10 in UEFI mode.

Congratulations! You have converted your MBR disk to GPT using DiskPart. ?

Method # 3: with Gptgen

Gptgen is a tool that allows converting MBR disks to GPT without data loss.

advice : if you want to convert your system disk (the one you plan to install Windows on) in GPT to take advantage of the features offered by UEFI, here is what I recommend depending on your situation:

  • To install Windows 10: use the MBR2GPT tool instead, which allows you to convert a system disk lossless of data.
  • To install Windows 7 or 8.1: convert your disk with loss data using Diskpart. This is because Gptgen is not an official tool, so there are chances that the conversion will fail and you will lose your data. It is better to save your data to external media, erase and then convert the disk to GPT to finally install Windows in UEFI mode.

Here is how to convert MBR disk to GPT with Gptgen :

  1. Download Gptgen.
  2. Unzip the archive at the root from your disk (C :).
  3. Open a Command Prompt from this folder. To do this, while holding the key Maj ⇧ down, right-click on an empty area and select Open a command window here.
  4. Identify the number disk to convert to GPT:
    list disk
  5. Convert the disk in GPT (replace 0 by the disc number):
    cd C:gptgen-1.1
    gptgen.exe -w \.physicaldrive0
  6. Restart your PC for the changes to take effect by Windows.

Congratulations! You have converted your MBR disk to GPT without data loss using Gptgen. ?

Method # 4: Using the Disk Management Tool

! Attention : all data on your disk will be erased.

  1. Open the tool Disk management :
    • via the Start menu or the Research :
    • via le Quick Link menu :
    • away there Run command : diskmgmt.msc.
  2. Change the display to view the format (MBR or GPT) of the disks: View> Top> Disc List.
  3. Identify the disk to convert to GPT. Here is “Disk 1”.
  4. Delete all volumes from the disk: right click on each volume> Remove volume.
  5. The disk now has unallocated space.
  6. Convert disk to GPT by right clicking disk> Conversion to GPT disk.
  7. There you have it, the disk has been converted to GPT! All you have to do is create volumes on it to be able to use it.

Congratulations! You have converted your MBR disk to GPT using the Disk Management tool. ?

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