How to Convert MBR to GPT Partition without Data Loss

How to Convert MBR to GPT Partition without Data Loss

The Master Boot Record (MBR) partitioning system has been around for decades and has been the standard method for partitioning hard drives in computers. However, it has limitations in terms of the number of partitions it can handle and its lack of support for disks larger than 2TB. As a result, newer technologies like GUID Partition Table (GPT) have become increasingly popular, offering better compatibility with modern PCs and larger disk sizes. Additionally, Windows 11 requires a GPT partition scheme to be able to install and function properly. Therefore, users with older computers that use MBR might need to upgrade their hardware or switch to a newer partition scheme to use Windows 11. In this blog, I will explain how to convert MBR to GPT in order to meet the system requirements for Windows 11. Converting from MBR to GPT will allow users to install and run Windows 11 smoothly on their older hardware

Before you begin, it is essential to backup your data, as converting MBR to GPT will erase all data on the disk. Also, ensure that your system supports UEFI and not BIOS, as GPT is only supported by systems that use UEFI.


  1. There should be no more than three primary partitions in the MBR partition table, including the 100MB system partition mentioned below:
    • System (Active, Primary Partition)
    • C Drive (Boot, Page File, Cash Dumps, Primary Partition)
    • D Drive (Primary Partition)
  2. All three partitions must be primary; you shouldn’t have any extended or logical partitions.
  3. If you have more than three partitions, you must delete the least important partitions after backing up the important data.
  4. You must have an active partition in your MBR partition style.

In Microsoft Windows, you can find out information regarding the partitions by going to the Disk Management Tool, which shows you all of the partitions on your hard drive. To launch the disk management tool, right-click on the Windows Start menu or Windows key + X, and select Disk Management. You can also launch it by typing “diskmgmt.msc” in the Run window (Windows key + R). This tool lets you manage your hard drives, partitions, and volumes. For example, you can format, extend, shrink, and give drive letters to your hard drives. Additionally, you can view disk information such as size, free space, and file system type.

Disk Management Tool showing details about disk partitions
Disk Management Tool showing details about disk partitions

Open Command Prompt as an administrator

To convert an MBR partition to GPT, you need to use the Command Prompt with administrative privileges. To open Command Prompt as an administrator, follow these steps:

  • Click on the Start menu and search for “Command Prompt.”
  • Right-click on the Command Prompt app and select “Run as administrator.”

Disk Validation Phase

The validation process will ensure that there are no errors or issues with the disk before proceeding with the conversion process. Run the below command to validate the disk before converting it from MBR to GPT format.

mbr2gpt.exe /validate /disk:0 /AllowFullOS

If the validation process went well, you’ll see the screenshot above, which shows that the disk is ready to be converted.

mbr2gpt utility showing the disk validation process

If there are errors or issues, the tool will give an error message, as shown in the screenshot below.

mbr2gpt utility showing the disk validation process

In this case, you need to make sure that all the requirements are met and that all the right information is given. If everything seems to be in order, you may need to look for technical assistance.

Disk Conversion Process

After you’ve finished the validation phase successfully, you need to start the conversion process by typing in the command demonstrated below.

mbr2gpt.exe /convert /disk:0 /AllowFullOS

The disk conversion process will take some time to complete, so it’s important to be patient and let the computer work until the process is finished. In order to prevent data loss do not stop or interrupt the conversion process. Once the conversion is done, check the content of the converted disk to make sure that all of the data was transferred correctly to the new partition format.


Using the command line utility mbr2gpt to change an MBR partition to a GPT is a straightforward process that can be done without losing any data. But it’s important to back up important data before making partition changes to reduce the chance of losing data if something goes wrong.

I hope the above information can be helpful to you, please do not hesitate to contact me if you have any questions or concerns. I will welcome the opportunity to provide further support and assistance as needed. Thank you for considering this information, and feel free to reach out at any time.

Image Credit: Image by Freepik

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