How to change legacy to UEFI without reinstall windows 10? Microsoft has added useful tools that didn’t exist in early versions of Windows and even some older versions of Windows 10 in the last few years. The MBR2GPT tool allows Windows 10 users to convert BIOS from Legacy to UEFI without reinstalling Windows 10. You can call the MBR2GPT tool using Command Prompt and switch from Legacy BIOS to UEFI with just two commands.
Which is better: Legacy BIOS or UEFI
bios (main input/output system) is a piece of code that your microprocessor needs to set up after pressing the power button of the computer. bios first appeared a long time ago and worked perfectly well, though it also had limitations.
For example, BIOS uses Master Boot Record (MBR) to define the maximum partition capacity of 2.2 TB. Hardware improvements over the past decade and a half created a new firmware form, followed by the appearance of UEFI (integrated extendable user interface).

UEFI, just like other bios types, is a low-level software that your computer runs when you press the power button and before launching the operating system. UEFI is stronger and does not have limitations related to Legacy BIOS.
For example, UEFI supports up to 9ZB partitions, offers faster boot times and has security features such as Secure Boot.
Preparing to Convert Legacy BIOS to UEFI
Before we talk about switching BIOS from Legacy to UEFI, you need to consider a few points.
check your bios version
Make sure you are currently using Legacy BIOS. You definitely don’t want to go through the whole process and then realize that you were using UEFI the whole time!
Open the Disk Management app to check which version of BIOS you are running. Create and format hard disk partitions in the Start menu and open the option that matches the most. This will take you to the Disk Management app.

In the app, right-click the disk you installed Windows on and select Properties.

Next, you need to check the type of partition of your disk to make sure you are using Legacy bios or UEFI. If you are using legacy BIOS, your disk partition type will be MBR. But if you are using UEFI, the disk partition type will be GPT type.
You can check the disk partition type on the Volumes tab in Properties. In the Disk information section, search for partition style.

check your windows version
The MBR2GPT tool is available in Windows 10 version 1703 and up. Before starting the process, make sure you have the right version by searching for winver in the Start menu and opening the option that matches the search term the most. The new window that opens will display the Windows version on the second line.

Prerequisites for converting BIOS from Legacy to UEFI
In addition to making sure you’re using Legacy BIOS, you’ll need to check a few more and change them if needed.
1- Make sure that the target disk (i.e. the disk containing Windows) has three partitions or less (drive C, D, etc.). You can view partitions by pressing Win+R and running diskmgmt.msc. If you see more than three partitions, you’ll need to merge or delete them.
2- If you have encrypted the target disk using BitLocker, this will disrupt the conversion process. Since Windows doesn’t convert an encrypted disk, you’ll need to disable BitLocker before you start doing so.
3- After conversion, you cannot boot Windows until you change the motherboard weir form settings from Legacy BIOS to UEFI. Quickly move from Legacy BIOS to UEFI, looking for settings that allow you to switch from Legacy BIOS to UEFI before you start converting. This process is different in different motherboards. So you may need to look for it a little bit. If you can’t find the settings, you can use the manual.
4- make a backup of your important information.
How to change BIOS from Legacy to UEFI
How to change the BIOS from Legacy to UEFI
Once you are sure that everything is in order, it is time to use the MBR2GPT tool.
1. Search for cmd in the Start menu, right-click on it and select Run as administrator.
2- Your disk must have the MBR2GPT tool conversion conditions to be able to do this. Check to see if it does this by confirming the disk using the following command:
mbr2gpt /validate /disk: 0 /allowFullOS
If the disk you want to convert is not disk 0, replace 0 with the appropriate disk number.
If your disk does not meet the conversion requirements, you will see an error. For example, the following error is caused by a USB drive validation.

3- if validation is successful, run the following command to start conversion:
mbr2gpt /convert /disk: 0 /allowFullOS

allow the conversion process to be completely finished. the process takes only a few seconds.
4- Restart your computer and go to your motherboard weir form to change settings. Assuming you learned how to log in to the BIOS before starting the process, this will only take a few seconds. In most cases, you’ll see an option to select boot mode on the Boot tab or section in your weir form.

5- boot windows.
6- Check that you have successfully converted the partition using the same method you used before. Go to the Disk Management program, right-click on the converted disk, select Properties> Volume, and this time the GUID Partition Table (GPT) in front of partition style should be seen.
enjoy your modern bios
UEFI has a lot of functionality. Given that most modern systems use UEFI, it’s natural to want to Convert Legacy BIOS to UEFI.
well, it’s over! fortunately, you didn’t need to reinstall windows either.