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10 Tech How-To

Check if Windows Uses UEFI or Legacy BIOS

Guide 10-29340 · Updated · Step by step

This guide shows you how to determine whether your Windows PC boots in UEFI mode or legacy BIOS mode. Knowing this matters when installing an operating system, enabling Secure Boot, or troubleshooting boot problems. You only need a few minutes and access to Windows—no extra tools required.

What You’ll Need

  • A PC running Windows 10 or Windows 11 (the steps work on Windows 8 too).
  • Administrator access is not required for most methods, but the Command Prompt method may need it.

Step-by-Step

  1. Open System Information. Press Windows + R to open the Run dialog, type msinfo32, and press Enter. This opens the System Information window.
  2. Find the BIOS Mode entry. In the System Summary section (which is selected by default), look for the line labeled BIOS Mode. It will show either UEFI or Legacy (sometimes called “Legacy BIOS” or “BIOS”).
  3. Interpret the result. If it says UEFI, your system uses UEFI. If it says Legacy, your system uses the older BIOS mode.
  4. Alternative method using Command Prompt. Open Command Prompt (search “cmd” in the Start menu, right-click and select “Run as administrator” if possible), type bcdedit /enum firmware, and press Enter. If you see a section titled “Firmware Boot Manager” with entries that include “UEFI,” your system is in UEFI mode. If you see nothing related to UEFI, it is likely legacy BIOS.
  5. Alternative method using Disk Management. Press Windows + X and select Disk Management. Right-click on the disk that contains your Windows installation (usually Disk 0) and choose Properties. Go to the Volumes tab. Look at the Partition style field: if it says GUID Partition Table (GPT), you are likely in UEFI mode; if it says Master Boot Record (MBR), you are likely in legacy BIOS mode. Note: this method is not 100% conclusive because you can have a GPT disk with legacy BIOS in some rare configurations, but it is a good secondary check.

Common Mistakes

  • Confusing “BIOS” in System Information with legacy mode. Even in UEFI systems, the System Information window may show “BIOS Version/Date” and “BIOS Mode” as “UEFI.” The “BIOS” label is just a generic term—focus on the “BIOS Mode” field.
  • Assuming that having a GPT disk means UEFI. While UEFI is required for booting from GPT in most cases, some older systems can boot from GPT with legacy BIOS using special boot managers. Always check the BIOS Mode field in System Information for the definitive answer.
  • Checking the wrong disk. If you have multiple disks, make sure you check the one that contains the Windows boot files, not just a data drive.

Tips

  • Use System Information as your primary method. It is the most straightforward and reliable way.
  • If you are planning to install Windows, knowing your boot mode helps you choose the correct installation media. UEFI systems typically require a 64-bit installer and often support Secure Boot.
  • Check your motherboard manual if you need to change the boot mode. The option is usually called “Boot Mode,” “UEFI/Legacy,” or “CSM” (Compatibility Support Module) in the BIOS setup.
  • For Windows 11, UEFI is mandatory, so if you are checking compatibility, this is a key step.

Troubleshooting

If the System Information window does not show a “BIOS Mode” field, it may be because your system is very old or the information is hidden. Try the Command Prompt method instead. If that does not work either, restart your computer and enter the BIOS/UEFI setup (usually by pressing Del, F2, F10, or Esc during startup—check your motherboard manual). Look for a boot mode or UEFI/Legacy setting; the current mode is usually displayed there.

If you cannot open System Information at all, try pressing Windows + S, type “system information,” and click the result. If that fails, you can also run msinfo32 from a Command Prompt window.

Frequently Asked Questions

Can I switch from Legacy to UEFI without reinstalling Windows?

Yes, but it is risky and not officially supported by Microsoft. You would need to convert your system disk from MBR to GPT using a tool like MBR2GPT, then change the BIOS setting. Back up your data first, and be prepared for potential boot issues.

Does UEFI make my computer faster?

UEFI itself does not significantly improve performance, but it offers faster boot times and better security features like Secure Boot. The difference is most noticeable when booting from a fast SSD.

How do I know if my motherboard supports UEFI?

Most motherboards manufactured after 2012 support UEFI. Check the manufacturer’s website or the manual. If your system came with Windows 8 or later, it almost certainly supports UEFI.

What is the difference between UEFI and Legacy BIOS?

UEFI is a modern replacement for the traditional BIOS. It supports larger hard drives (over 2 TB), faster booting, secure boot, and a graphical interface. Legacy BIOS is older and limited to MBR disks.

Can I use both UEFI and Legacy on the same computer?

Yes, many motherboards offer a “CSM” (Compatibility Support Module) that allows legacy BIOS boot. You can switch between modes in the BIOS setup, but you may need to change the disk partitioning scheme to match.

Does Windows 11 require UEFI?

Yes, Windows 11 requires UEFI with Secure Boot capability. If your system is in legacy BIOS mode, you will need to enable UEFI and convert your disk to GPT before upgrading.

Related

General steps for current mainstream versions; menus can differ by device and version. See the disclaimer or report an error.

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