How to change BIOS mode from Legacy to UEFI in Windows 10

This is a simple guide to help you change the BIOS mode from Legacy to UEFI in Windows 10. We promise it won't take more than a few minutes. 😄

The basic input/output system (BIOS) is the first thing you wake up when you turn on your computer. This ensures a proper handshake between the operating system and the connected hardware. And from that moment you start using your computer.

BIOS (also known as Legacy or Legacy BIOS) was good at what it did from 1975 to 2020; This year, chip manufacturers have gradually begun to move to an effective alternative: UEFI (Unified Extensible Firmware Interface).

Modernization guarantees:

  • Faster boot time and system performance
  • Support for hard drives (and partitions) larger than 2.1 TB.
  • More security and enhanced GUI
  • Boot support for both GPT (GUID Partition Table) and MBR (Master Boot Record) (via compatibility mode)

In addition, the ability of UEFI to use the GPT partition table does not imply a practical limit on the number of partitions.

Why switch from Legacy to UEFI in Windows 10?

UEFI has many advantages over Legacy BIOS such as:

Productivity increase Short loading time Convenient interface Supports larger hard drives and partitions than 2.1TB

Hence, it is more secure and improves the performance of your system.

How to change BIOS mode from Legacy to UEFI in Windows 10

This guide is divided into two parts:

  • Converting your hard drive from MBR to GPT
  • Enabling UEFI in BIOS settings (optional)

The second part depends on the manufacturer. So, check in advance and get comfortable before you start the first one. Chances are there won't be a UEFI option in the BIOS if you're using a really old PC.

But for the latter, you will have this option to switch to UEFI BIOS.

Before starting this guide, make sure that:

  • Do you have a complete backup of your system?
  • You have no more than three sections
  • Device encryption services such as BitLocker are disabled.

And yes, read no further if you are using Windows 11. In this case, your computer should already be running in UEFI. However, this is an important checklist item for Windows 10 users looking to upgrade to Windows 11.

Let's start with the main course.

Check current status.

Enter System Information in the search bar and click to open the corresponding result.

There you can check that the BIOS mode shows Legacy:

You can also confirm this with the disk type. Press Windows+R, type diskmgmt.msc and click OK.

This will open the Disk Management Console. Follow the instructions in this video and make sure you have a Master Boot Record (MBR) in the partition style listed under the Volumes tab.

So, now that we know that we have an MBR disk, we will try to convert it to GPR. This is done using the simple MBR2GPT tool that Microsoft ships with Windows 10 version 1703 or later.

You can check your version of Windows by typing winver in the Run box (Windows+R).

Since we have the right to use this tool, let's move on to the command line.

MBR to GPT conversion

Open a command prompt with administrator rights. To do this, type cmd, then click "Run as administrator" in the right pane.

After that type mbr2gpt /validate/allowFullOS at the command prompt:

Verify that the verification was successful. go through this solution from the Microsoft community if you get a disk layout check error.

After successful verification, type mbr2gpt /convert /allowFullOS and press Enter:

Failed to update ReAgent.xml is an error specific to my system. You may not receive it, and it won't affect the conversion process, even if there is one.

Finally, the process is complete and we have changed the BIOS mode from Legacy to UEFI.

And this screenshot confirms that:

Also, the disk management tools show that the partition style is GUID Partition Table (GPT). This process created a 100 MB EFI partition on the primary drive. You can verify this by noticing the change in the size of the primary partition, which has been reduced from 458.35 GB to 458.25 GB.

But your computer won't boot after that because the last step is to change the BIOS settings from Legacy to UEFI. As already mentioned, it depends on your PC manufacturer or your motherboard brand if you have a pre-built PC.

Summary

While it was easy to convert the BIOS mode from Legacy to UEFI on Windows 10, the average user might not need to. So make sure that you really need to do this before going through all these problems.

If it's not broken, don't fix it!

Instead, it's worth fixing the hearts of the countless people disenfranchised from Windows 11

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