Step-by-Step Guide: Converting MBR to GPT for UEFI on Windows 10 for Windows 11

If you want to switch the firmware type from the Basic Input/Output System (BIOS) to the Unified Extensible Firmware Interface (UEFI) without modifying the current installation or plan to upgrade from Windows 10 to Windows 11, you can use the "MBR2GPT" tool to convert the drive from a Master Boot Record (MBR) to a GUID Partition Table (GPT) partition style.

Understanding BIOS and UEFI

BIOS is a piece of code that resides on the motherboard that connects the hardware and software. This code has been around for a long time, and while it worked well, it was never designed for modern hardware, and it had many limitations, including limitations to partitions smaller than 2TB.

UEFI is the new firmware type designed to replace the old BIOS style. It introduces additional features, including support for partitions larger than 2TB and faster startup, sleep, resume, and shutdown times. Also, it unlocks new security features available on Windows 11 and Windows 10. For instance, "Secure Boot" is a feature that can protect a device's startup process from malicious programs, and now it's a prerequisite to install Windows 11. "Device Guard" gives you more advanced controls for app access, and "Credential Guard" can help prevent pass-the-hash attacks.

In this how-to guide, I'll walk you through the steps and information to use the Microsoft MBR2GPT command-line tool to convert a drive from MBR to GPT partition style, switch from BIOS to UEFI mode on your device, and enable Secure Boot correctly.

Warning: This is a non-destructive process, but it's still recommended to make a full backup of your PC before proceeding in case something goes wrong and you need to recover your setup.

How to convert a drive from MBR to GPT on Windows 10

Unlike older methods that require data backup and Windows reinstall, the MBR2GPT tool enables quick partition style changes. The conversion process adds the GPT components to the MBR partition without modifying the existing partition and leaving the data untouched.

The best approach is to switch to UEFI and perform a clean install of Windows 11. However, if you already have a Windows 10 installation and want to upgrade, you can convert the drive to change the system firmware settings properly. Otherwise, the Windows 11 setup won't let you proceed.

Check MBR or GPT partition style

Before making system changes, check the current settings to see whether the system is set to MBR or GPT using these steps:

1. Open Start.
2. Search for Disk Management and click the top result to open the experience.
3. Right-click the drive (where Windows 10 resides) and select the Properties option.

4. Click on the Volumes tab.
5. Under the "Partition style" field, if the field reads "GUID Partition Table (GPT)," the drive does not need conversion, but if you see the "Master Boot Record (MBR)" label, you will need to use the conversion tool.

6. Click the Cancel button.

Once you complete the steps, you can change the partition style on the computer.

Also, if you need to change the partition, check your device manufacturer's support website to find out whether the hardware includes support for UEFI before using these instructions.

Convert MBR to GPT partition style (offline)

To convert a drive using MBR to GPT on Windows 10, use these steps:

1. Open Settings.
2. Click on Update & Security.
3. Click on Recovery.
4. Click the Restart now button under the "Advanced startup" section.

7. Click the Troubleshoot option.
8. Click on Advanced options.
9. Click the Command Prompt option.

8. Select your administrator account and sign in (if applicable).
9. Type the following command to validate the drive's requirements and press Enter: mbr2gpt /validate

• Quick tip: The mbr2gpt.exe is located in the "System32" folder inside the "Windows" folder. If you want to see all the available options, use the mbr2gpt /? command.

10. Type the following command to convert the drive from MBR to GPT and press Enter: mbr2gpt /convert

• Quick note: The command output in this image indicates that the conversion has completed successfully, but there was an issue with the Windows Recovery Environment. If this happens, once you're in the desktop, run the reagentc /disable and reagentc /enable commands from Command Prompt (admin) to delete and recreate the recovery environment experience.

11. Click the Close button.
12. Click the "Turn off your PC" option.

After you complete the steps, the tool will validate the drive and create an EFI system partition (ESP). The process will also insert the UEFI boot files and GPT components into the partition. The tool will update the Boot Configuration Data (BCD) and add the previous drive letter to the drive.

Convert MBR to GPT partition style (online)

To minimize potential problems, the MBR2GPT tool should always be used offline. However, it can also be run when the system is operational.

To convert a drive from MBR to GPT on Windows 10, use these steps:

1. Open Start.
2. Search for Command Prompt, right-click the top result, and select the Run as administrator option.
3. Type the following command to validate the drive and press Enter: mbr2gpt /validate /allowFullOS

4. Type the following command to convert the drive to GPT and press Enter: mbr2gpt /convert /allowFullOS

Once you complete the steps, the command-line tool will reduce the size of the primary partition and change it from MBR to GPT.

MBR2GPT return codes

If the processes are completed successfully, the return code would be "0," but if the process fails, you may see one of the 11 error codes:

MBR2GPT important details

The MBR2GPT tool is compatible with traditional hard drives (HDD), solid-state drives (SSD), and NVMe M.2 drives on virtually any version of Windows 10, provided it is run from a Windows 10 installation (version 1703 or later).

When dealing with a drive using file encryption with BitLocker, you must first suspend the encryption before following the outlined instructions.

While MBR-style drives can have up to four primary partitions, the drive you want to convert can only have three partitions because one additional allocation is required to create the UEFI partition.

Finally, Microsoft designed the tool to convert drives running Windows 8.1, 7, or an older version. However, you can always upgrade the installation to the latest release of Windows 10 and then use the tool to convert from MBR to GPT.

How to change the firmware mode from BIOS to UEFI

After converting the drive to the GPT style, the computer will no longer start until you change the firmware type from BIOS to UEFI in the motherboard.

Typically, this process requires hitting one of the function keys (F1, F2, F3, F10, or F12), the "Esc," or the "Delete" key as soon as you start the device. However, since these options are always different, it's best to check your device manufacturer's support website for more specific details.

On the firmware interface, find the "Boot" menu, enable the UEFI option, save the changes, and then the computer should start normally.

Also, if you plan to upgrade the device to Windows 11 while in the UEFI settings, open the boot or security settings page, enable the "Secure Boot" option, exit the firmware, and save the changes.

Check GPT partition style

To confirm the device is using a GPT partition style, use these steps:

1. Open Start.
2. Search for Disk Management and click the top result to open the app.
3. Right-click the main drive and select the Properties option.

4. Click on the Volumes tab.
5. Under the "Partition style" field, the information should now read "GUID Partition Table (GPT)."

After you complete the steps, if the partition is running using the correct partition style, you only need to check whether the device uses the UEFI firmware mode.

Check UEFI firmware

To confirm the computer is in UEFI mode and Secure Boot is turned on, use these steps:

1. Open Start.
2. Search for msinfo32 and click the top result to open the System Information app.
3. Click on System Summary on the left pane.
4. Check the "BIOS Mode," which now should read UEFI.

5. Check the "Secure Boot State" information, which now should read On.

Once you complete the steps, if the System Information displays the mode as "UEFI," you have successfully switched the firmware type.

It's important to note that Windows 10 is no longer a supported operating system. If you're still running the operating system, it's recommended to upgrade to Windows 11 as soon as possible.

Alternatively, Microsoft offers the Extended Security Updates (ESU) program that extends security updates for another year. However, this isn't a permanent solution. Instead, it's a temporary option to plan how you will be upgrading to Windows 11 or switching to a new computer.

FAQs about converting from MBR to GPT

These are common questions regarding the partition type from MBR to GPT.

More resources

For more helpful articles, coverage, and answers to common questions about Windows 10 and Windows 11, visit the following resources:

• Windows 11 on Windows Central — All you need to know
• Windows 10 on Windows Central — All you need to know

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