3 Quick Methods to Check if Windows is Using UEFI or Legacy

Whether you are trying to upgrade to Windows 11, enable Secure Boot to play modern video games like Valorant, or install a hard drive larger than 2TB, your computer needs to be running in UEFI mode.

Historically, older computers utilized "Legacy BIOS," a classic firmware that relies on the Master Boot Record (MBR) partition style. Modern PCs use UEFI (Unified Extensible Firmware Interface), which relies on the much more robust GUID Partition Table (GPT) format.

If you aren't sure which firmware your PC is currently utilizing, don't worry. In this guide, we will show you three incredibly fast ways to check if Windows is using UEFI or Legacy, and explain exactly how to upgrade your system without losing any of your files.

Check the BIOS Mode Without Accessing BIOS on Your PC/Laptop

No matter what error you met, first, let’s see how to check your boot mode on your computer.

Method 1: The 1-Minute Check Using System Information (msinfo32)

The absolute fastest and most reliable way to check your current BIOS mode is through the native Windows System Information tool. This method works perfectly on Windows 10 and Windows 11.

Step 1. Press the Windows Key + R simultaneously to open the Run dialogue box.

Step 2. Type msinfo32 into the box and click OK (or press Enter).

Step 3. The "System Information" window will pop up. Ensure System Summary is highlighted in the left-hand navigation pane.

Step 4. Scroll down the right-hand panel until you find the item named BIOS Mode.

Method 2: Check Using Windows Disk Management (Visual Method)

Many tech tutorials forget this method, but checking your disk partitions is a fantastic visual way to confirm your boot mode. UEFI systems require a dedicated "EFI System Partition" to boot, whereas Legacy systems do not.

Step 1. Right-click the Windows Start button and select Disk Management from the menu.

Step 2. Maximize the window so you can clearly see the layout of "Disk 0" (which is typically your C: Drive where Windows is installed).

Step 3. Look at the individual partition blocks on that disk.

• If you see an "EFI System Partition" (usually around 100MB): Your computer is definitely utilizing UEFI.
• If you see a "System Reserved" partition but NO EFI partition: Your computer is currently using Legacy BIOS, and the disk is formatted as MBR.

Method 3: Check Using the DiskPart Utility (Command Prompt)

Because UEFI firmware mandates the use of a GPT disk structure, checking if your system disk is GPT is a guaranteed way to know if you are using UEFI. You can check this rapidly using the Command Prompt.

Step 1. Press the Windows key, type cmd, right-click Command Prompt, and select Run as administrator.

Step 2. Type diskpart and press Enter.

Step 3. Type list disk and press Enter.

Step 4. A list of all connected drives will appear. Look under the far right column labeled "GPT".

• If there is an asterisk (*) in the GPT column next to your OS drive, you are using UEFI.
• If the GPT column is blank, your drive is MBR, which means Windows is currently booting in Legacy mode.

🤔 I have a legacy BIOS. How Do I Change to UEFI?

If your BIOS mode says "Legacy," your system disk is currently using the MBR partition style.

While Microsoft offers a native command-line tool called MBR2GPT.exe, it is notoriously tedious. It requires precise syntax, often fails with a "cannot find OS partition" error, and carries a high risk of data loss if a command is typed incorrectly.

The smartest, safest alternative is to bypass the command prompt entirely and use a professional GUI partition manager.

The Safest Solution: Convert MBR to GPT with AOMEI Partition Software

If you need to change your firmware to UEFI without losing any of your applications, games, or files, AOMEI Partition Software is the industry-standard solution. Unlike native Windows tools that require disk wipes or complex coding, AOMEI allows you to securely convert your active Windows system drive from MBR to GPT in just three simple clicks.

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Advanced Windows Disk Partition Manager

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• Flexible Disk Converter: Convert disks between MBR and GPT without deleting partitions, switch between basic and dynamic disks, and convert NTFS and FAT32 file systems.
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Step-by-Step Guide to Safely Convert to GPT:

Step 1. Download, install, and open AOMEI Partition Software.

Step 2. On the main dashboard, right-click the MBR system disk (usually Disk 0) and select "Convert to GPT" from the drop-down menu.

Step 3. A confirmation window will appear asking if you are sure you want to convert the disk. Click OK.

Step 4. You will return to the main interface. Click Apply in the top-left corner, and then hit Proceed to execute the operation.

Because you are converting your active operating system drive, AOMEI will safely perform this task in PreOS mode and automatically restart your PC.

Step 5 (Final Step). As your PC reboots, rapidly press your motherboard's BIOS key (usually F2, F12, DEL, or ESC). Navigate to the "Boot" tab and change your Boot Mode from Legacy to UEFI. Save your changes and let Windows load normally.

Ending

Checking whether your computer is using UEFI or Legacy takes less than a minute using the msinfo32 command or Windows Disk Management.

If you discover you are running Legacy, don't let it stop you from enjoying the modern security features of Windows 11. By using AOMEI Partition Software, you can safely upgrade your system's partition style from MBR to GPT in minutes, entirely bypassing the risk of data loss and command prompt headaches.

FAQs: About UEFI Mode

1. Why does Windows 11 require UEFI?

A: Windows 11 utilizes advanced security protocols, primarily Secure Boot, to protect your computer from malware that attempts to load before the operating system boots. Secure Boot is a feature that is strictly exclusive to UEFI firmware and cannot run on Legacy BIOS.

2. Will I lose data changing from Legacy to UEFI?

A: If you use the Windows native diskpart tool to convert your drive to GPT, yes, it will wipe all of your data. However, if you use a safe third-party tool like AOMEI Partition Software, you can successfully transition from Legacy to UEFI with 100% of your data perfectly preserved.

3. Can my old motherboard support UEFI?

A: Most motherboards manufactured after 2012 support UEFI natively, or offer a "CSM" (Compatibility Support Module) that allows them to switch between Legacy and UEFI. If your PC is incredibly old (built before 2010), it may only support Legacy. You can check your motherboard manufacturer's website to confirm.