Every time you turn on your computer, you are sometimes greeted by a screen that displays the manufacturer's information. This is called the BIOS, and it has two main types; Legacy BIOS and UEFI. Older motherboards have legacy BIOS firmware while modern computers come with the UEFI BIOS.

It is possible to completely change the BIOS on your computer, but do so with caution: If you don't know what you're doing, it could lead to irreversible damage. We have put together this guide to help you upgrade from Legacy BIOS to UEFI. Let's get started!

Why Should You Convert Legacy BIOS to UEFI?

Whenever you turn your computer on, you are actually activating the BIOS, which loads the rest of your computer’s hardware. The BIOS of a computer determines how the PC will turn on, from which drive it will boot, and how it will perform basic functions.

Additionally, it is used for identifying and configuring items such as hard drives, floppy drives, optical drives, CPUs, memory, and other equipment in computers.

Old computers come with the Legacy BIOS, which manages the data flow between your operating system and connected devices. However, it has certain limitations. For instance, it cannot recognize drives larger than 2.1TB, and the setup programs are text-only.

On the other hand, modern PCs come with UEFI BIOS, which is extensively customizable and does the same job better. UEFI can support drives 2.2TB or larger thanks to its use of GUID Partition Tables (GPT) instead of the outdated Master Boot Record (MBR). The UEFI stores all the information about initialization and startup in an EFI file called .efi, which resides on an EFI System Partition called ESP. A boot loader program for the operating system installed on the computer is also included in the ESP partition.

To put it simply, switching to UEFI is a worthwhile upgrade that provides you with the following advantages:

  • Better performance of the computer as a whole
  • Fast booting times
  • Removes compatibility issues with Legacy BIOS

Additionally, UEFI is more secure than Legacy BIOS. UEFI's Secure Boot feature ensures that only approved operating systems can be installed on your computer. However, UEFI can still be vulnerable to certain security attacks.

How to Check if You Are Using Legacy BIOS

You can determine your BIOS version by following these steps if you are not sure which version you are using:

  1. Type Create and format hard disk partitions in the search area of the taskbar and click Open. This should launch the built-in Disk Management tool.
    Launch the Disk Partition utility
  2. In the Disk Management tool, right-click on the Windows installation disk (Disk 0) and select Properties from the context menu.
    Launch Disk Properties
  3. Go to the Volumes tab inside the Properties window. If you locate Master Boot Record (MBR) next to Partition style, your system is using Legacy BIOS.
  4. If you see GUID Partition Table (GPT) instead, then your system is on UEFI already, and you don’t need to do anything else!
    GUID Partition Table

Following your determination of which BIOS you are using, you can move on to the practical steps.

The Prerequisites for Upgrading to UEFI

Before you jump into converting Legacy BIOS to UEFI, here are a few things you should know:

  1. Your Windows version should be Windows 10 v1703 or higher. In case you do not know which operating system version you are on, press Win + R keys simultaneously on your keyboard. In the text field of the dialog box, type winver and hit Enter. In the About Windows box, you should see your current Windows version.
    Current Windows version
  2. Your targeted disk shouldn't contain more than three partitions. If more than three partitions are present on the Windows 10 installation drive, you can merge or delete them.
  3. BitLocker does not allow Windows to convert your drive from Legacy BIOS to UEFI. This is why if you are using it, we suggest disabling or suspending BitLocker before you proceed.
  4. Once the conversion process is complete, you may have to change your firmware settings from Legacy BIOS to UEFI. As the process to switch from one to the other will vary depending on your motherboard manufacturer, ensure you have your manual with you.
  5. You will not lose your data during the conversion process. However, we recommend that you back up your data to be safe.

How to Convert Legacy BIOS to UEFI

Now that you have verified that your system is running Legacy BIOS and have created a backup of your data, let's begin the conversion process.

Here is what you need to do:

  1. Press Win + X keys on simultaneously on your keyboard.
  2. Select Shut down or sign out and then click on Restart while holding the Shift key from the context menu that appeared on your screen.
    Click on the Restart option to boot into Advanced Startup
  3. Your system should not boot into the Advanced Startup screen.
  4. From there, click on Troubleshoot.
    Troubleshoot option in Advanced Startup
  5. Select Advanced option in the next window.
    Select the Advanced option menu
  6. Now, click on Command Prompt.
    Choose the Command Prompt
  7. Once you are inside the Command Prompt window, type the command mentioned below and hit Enter to execute it.
    mbr2gpt /validate
    mbr2gpt /validate command
  8. This command should validate the targeted disk. Continue with the next step if the Validation completed successfully message is displayed. If any error is displayed, then this implies that the disk or system may not have the capacity to handle the conversion.
  9. In case you cannot validate using the command above, execute the following command.
    mbr2gpt /validate /allowFullOS
    mbr2gpt /validate /allowFullOS command
  10. Once the disk is validated, execute the following command to complete the conversion.
    mbr2gpt /convert
    mbr2gpt /convert command
  11. Windows should now begin the conversion process. Wait patiently for the process to complete and then reboot your PC.
  12. Upon rebooting, launch the firmware settings screen for your motherboard and switch it from Legacy BIOS to UEFI. Since the steps for this vary depending upon your motherboard, consult your manual for the exact procedure.
  13. Once done, follow the steps we outlined above to verify whether you've been converted from Legacy BIOS to UEFI.

BIOS Updated Successfully

The Legacy BIOS upgrade to UEFI has now been completed successfully. The UEFI system is more powerful and has more advanced features than BIOS. UEFI speeds up boot time and offers security features such as "Secure Boot," which prevents the computer from being booted by unauthorized or unsigned programs. This makes UEFI the next generation of BIOS.