Convert MBR to GPT Using mbr2gpt.exe in Windows 10

If you want to switch from the traditional MBR (Master Boot Record) format to GPT (GUID Partition Table) on your Windows 10 computer, the built-in mbr2gpt.exe tool allows you to do this easily and safely. This process lets you avoid reinstalling the OS and is ideal for enabling UEFI boot mode, which requires a GPT disk. In this guide, we’ll walk through the steps to correctly use mbr2gpt.exe.

Why Convert to GPT?

GPT offers several advantages over MBR:

  • More Partitions: MBR supports only up to 4 primary partitions, while GPT allows up to 128 partitions on a single disk.
  • Supports Large Drives: MBR works with drives up to 2 TB, whereas GPT can handle drives up to 18 exabytes.
  • Reliability: GPT uses redundant partition tables and checksums, which improve data integrity and reliability.

Preparation for Conversion

Before you begin, make sure that:

  • Your computer is running Windows 10 version 1703 or later (Creators Update).
  • The system is currently in BIOS mode, as UEFI mode will be required for booting after the conversion.
  • You have a backup of important data. Although mbr2gpt is designed for safe conversion, it’s always best to have a backup in case of unexpected issues.

Steps to Convert MBR to GPT Using mbr2gpt.exe

  1. Open Command Prompt as Administrator: Press Win + X and select Command Prompt (Admin).
  2. Run Validation Check: Run a check to ensure the disk is compatible for conversion. Type: 
    mbr2gpt.exe /validate
    If you receive a success message, proceed to the next step.
  3. Start the Conversion: To initiate the conversion, use the command: 
    mbr2gpt.exe /convert
    This command will begin the MBR to GPT conversion process. Note that the computer will restart automatically after completion.
  4. Switch BIOS Mode to UEFI: After rebooting, enter the BIOS settings and change the boot mode from Legacy to UEFI. Save your changes and restart the computer.

Verify Successful Conversion

To ensure the conversion was successful, open Disk Management (diskmgmt.msc) and check that your disk is now displayed as GPT. If you see “GPT (Partition Style),” the process was completed successfully.