How to check if PC uses BIOS or UEFI on Windows 10

• To check if the computer uses BIOS or UEFI on Windows 10, open System Information > System Summary, and confirm if the “BIOS Mode” is set to “BIOS” or “Legacy,” or “UEFI.”

UPDATED 10/24/2023: On Windows 10, you have multiple ways to check whether your computer uses a BIOS (Basic Input Output System) or UEFI (Unified Extensible Firmware Interface) firmware, and in this tutorial, I’ll show you the steps to complete this task.

BIOS is a small piece of software stored on a non-volatile chip on the motherboard, which instructs the system on how to boot and configure system hardware, such as hard drive, keyboard, mouse, processor, memory, and others.

Although BIOS has been around for many years and helps the operating system to interact with the hardware, it’s a system with some limitations, such as drive partition support, slow startup times, and it doesn’t offer security during startup.

UEFI is a newer firmware type that replaces BIOS and comes with a boot manager, delivers faster startup times, improves networking support, supports large partitions on drives, and offers security features to protect your system against bootkit and other malware attacks during startup.

While most devices already come with UEFI support, there are still many computers (especially older ones) that are still using BIOS. If you want to know which type of system your desktop, laptop, or tablet is using, you can check this information in at least two different ways on Windows 10.

In this tutorial, I’ll outline the two ways to check whether your computer uses BIOS or UEFI on Windows 10.

• 1. System Information
• 2. Setupact.log

Check if UEFI or BIOS on Windows 10

On Windows 10, you check the firmware type from the System Information app or from the SetupAct.log file available in the “Windows” system folder. Here’s how.

1. System Information

To confirm whether your computer uses UEFI or BIOS on Windows 10, use these steps:

1. Open Start on Windows 10.

2. Search for System Information and click the top result.

3. Confirm if the “BIOS Mode” is set to BIOS or Legacy under the “System Summary” section to determine whether the system uses BIOS.

   

4. Confirm if the “BIOS Mode” is set to UEFI under the “System Summary” section to determine whether the system uses UEFI.

   

Once you complete the steps, the System Information application will help you confirm the type of firmware type on Windows 10.

2. SetupAct.log

To determine if your device uses BIOS or UEFI through the setupact.log file, use these steps:

1. Open File Explorer.

2. Type the following path in the address bar and press Enter.

   %SystemRoot%\Panther

   

3. Open the setupact.log file using the Notepad.

4. Open the Find tool with the “Ctrl + F” keyboard shortcut.

5. Search for “Detected Boot Environment” and check:

   • If the line reads Callback_BootEnvironmentDetect: Detected boot environment: BIOS, then your computer uses BIOS.
   • If the line reads Callback_BootEnvironmentDetect: Detected boot environment: UEFI, then your device uses UEFI.
6. 

After you complete the steps, you will know the firmware type available on your computer.

You can also find out the version of the BIOS or UEFI with these instructions.

Although you can use these instructions on Windows 11, it’s unnecessary since the operating system only supports devices with UEFI, and you cannot install it using the BIOS mode. 

If you plan to upgrade to Windows 11 from 10, sometimes systems include an option to switch between these two types of firmware. However, you will have to check with your device manufacturer to confirm the support and the specific steps to switch from the Basic Input Output System to Unified Extensible Firmware Interface.

Update October 24, 2023: These instructions have been updated to ensure accuracy and reflect new changes.