If you've bought a system in the past couple of years, it probably supports both Legacy BIOS and UEFI. However, more often than not, legacy BIOS is the default. With a simple built-in tool, you can switch from BIOS to UEFI by converting Windows 10 from MBR to GPT. Let me show you how.
In case you don't know, compared the legacy BIOS, UEFI is plain better with a lot of features like faster startup and shutdown, pretty user interface, security features like Secure Boot, etc.
There are two major steps to use UEFI on an existing Windows 10 system that is running on Legacy BIOS. First, you need to convert Windows 10 from MBR to GTP. Second, you need to enable UEFI mode in your motherboard BIOS settings. Both these steps are important and should be followed in that order.
Warning: The process is irreversible. Follow the below steps only if you know what you are doing and at your own risk.
Important: Before making any changes to your system, create a complete backup. This allows you to restore the system if the results are undesirable or the system becomes unbootable.
Before you can switch from BIOS to UEFI, there are a couple of things you need to confirm.
- You should be using Windows 10 v1703 or higher. Know your Windows 10 version number.
- Verify if you are using Legacy BIOS or UEFI.
- The Windows 10 installation drive should not have more than three partitions. If you are using a separate drive, like an SSD, for Windows 10 then you should probably ok.
- If you are using BitLocker to protect your system. Decrypt the drive and disable BitLocker for the time being.
If any of the above conditions are not met, your system is not compatible and you should abandon the process.
Convert MBR TO GPT to Switch from BIOS to UEFI
To covert MBR to GPT, you need to execute a few commands from Advanced Startup options.
1. Open the PC Settings app by pressing the Win + I keyboard shortcut.
2. In the PC Settings app, go to "Update & Security -> Recovery" page and click on the "Restart Now" button under "Advanced Start-up" section.
3. The above action will restart your system and takes you the advanced startup options screen. Here, go to "Troubleshoot -> Advanced Options" and then select "Command Prompt".
4. If you are asked to choose an account, select an administrator account and verify yourself by providing the account password.
5. In the command prompt window, execute the following command. This command will validate your installation. If your system is compatible, you will not see any errors in the response of the command.
6. Once the validation is done successfully, execute the below command.
As soon as you execute the command, it will create a new EFI partition and places all the necessary UEFI boot files and other GPT component files in that partition. Finally, it will update the Boot Configuration Data (BCD) to reflect the changes so that you can boot into your system.
Once you see the success message, close the command prompt window and restart the system
Important Additional Step
After converting Windows 10 from MBR to GPT, you should also make sure that the motherboard is set to use UEFI and not the legacy BIOS. Depending on your motherboard model and manufacturer the actual steps will be different. So, consult the motherboard manual or manufacturer website to enable UEFI mode.
If you don't do this, you will not be able to boot into Windows 10.
Problem: Can't Boot
If you can't boot into your system after converting from BIOS to UEFI, I recommend you restore the default motherboard settings (i.e, use Legacy BIOS) and restore Windows with the backup you took earlier.
Alternatively, you can just reinstall Windows 10 with UEFI turned on. This will make sure that Windows will use GPT rather than MBR. Of course, reinstalling Windows 10 means that you have to reinstall and configure all your applications and games. If you choose to reinstall Windows 10, create a UEFI bootable Windows 10 installation drive. So, keep that in mind before nuking the current installation.
That is all. If you need anything or stuck somewhere, comment below and I will try to help as much as possible.