How to Convert MBR to UEFI Without Reinstalling Windows
Converting MBR (legacy) to GPT(UEFI) is necessary if you want better use of disk for some Windows systems.
Strictly speaking, you can't change MBR to UEFI, because MBR is a partition table, and UEFI is a boot mode.
MBR is the breviation for Master Boot Record that is used to describe how and where the disk information store. If the MBR is corrupted, the OS can't be retrieved by your computer. And the UEFI boot mode. The other partition is GPT, which is newer and better for many circumstances.
UEFI and Legacy BIOS uses different process to start a computer. And UEFI is the successor to BIOS. And usually, MBR disk + BIOS boot mode, and GPT disk + UEFI boot mode are 2 combinations that mostly used.
Next, we will give you more detail of MBR and GPT, BIOS and UEFI and demonstrate how to convert MBR to GPT and change BIOS to UEFI.
Legacy BIOS is a very important firmware that is used to initialize hardware on your PC during the boot process. And a computer won't be started successfully until the BIOS activate all the necessary components for booting up.
After decades of service, Legacy BIOS is gradually replacing by the new firmware-UEFI (Unified Extensible Firmware Interface), which is easier-to-use. UEFI is much better than Legacy BIOS in many aspects.
● Better compatibility：UEFI works well with the newer partition table, GPT while BIOS cannot support Windows booting from a GPT disk.
● Larger capacity support: UEFI mode allows you to use a disk with a large capacity while BIOS cannot support a disk more than 2TB.
● Faster speed: The UEFI boot process is faster than BIOS. UEFI directly boots the operating system and saves the BIOS testing process. And the BIOS will wake up the hardware firstly, and then load bootloader to initialize Windows.
You have known the difference between BIOS and UEFI, there are brief introductions about MBR and GPT. They are different partition table formats, and GPT is the successor of the MBR so it comes with lots of benefits over MBR:
● GPT supports a disk larger than 2 TB in size while MBR cannot.
● A GPT disk supports volumes up to 18 exabytes and 128 partitions per disk while the MBR disk supports 2 terabytes in size and 4 primary partitions at most.
● GPT partitioned disks have redundant primary and backup partition tables for improved partition data structure integrity.
Although UEFI can support MBR disk, MBR plus BIOS, GPT work with UEFI are better for you if you want better use of disk, and break the limit of 2TB. Next, we will show you how to convert MBR to GPT and convert legacy BIOS to UEFI.
✍Tip: Click this link to know more information about MBR and GPT: MBR vs GPT: Which One Is Better for You?
Before converting MBR(Legacy) to GPT(UEFI) you need to：
1. Ensure your computer is running with Windows 64-bit 7, Windows 8/8.1, or Windows 10 operating systems
2. Make sure your computer supports both BIOS and UEFI. If you don’t know, you can press “Win + R” to open Run, and type “msinfo32” to open System Information. And look up “BIOS Mode” to check if your PC supports both Legacy BIOS and UEFI.
To convert legacy BIOS to UEFI without reinstalling Windows, firstly, you need to convert MBR to GPT. Follow the context, there are 2 methods for you to convert MBR to GPT for you.
If you have an installation CD, you can convert MBR to GPT with Diskpart.
1. Insert the installation CD into your computer, and boot the computer from the CD
2. Then press “shift＋10” to open Command Prompt.
In the Diskpart Window, input the following commands and execute them one by one.
● list disk
● select disk 1(the disk number of your system disk, normally it is disk 1)
● convert gpt
Diskpart is a good way to convert files system for computer experts. But you may don’t installation CDE. Moreover, it will erase all data on the disk, and it is complicated for a novice. An unexpected mistake probably would bring about some issues since the operation can’t be revoked.
Fortunately, there is a great tool-AOMEI Partition Assistant Professional for you. With this software, you convert MBR to GPT without reinstalling Windows system and deleting partitions/data loss. let’s see the specific steps. You can download the Demo version to have a try.
Step 1. Install and open AOMEI Partition Assistant. Right-click the system disk and select “Convert to GPT disk".
Step 2. Ensure you have converted Legacy BIOS to UEFI, and click “Yes” to confirm.
Step 3. In the main interface of AOMEI Partition Assistant, click “Apply” to start the conversion.
And wait for the operation to complete. After that, you can go to “This PC” and open the “Properties”, and you will see the partition table has become to GPT.
After converting MBR to GPT, follow the steps to change BIOS to UEFI.
1. Start your computer and press the functional key (generally, it is F1, F2, F3, F10, or F12, ESC) to enter the firmware interface when you see the first screen. The functional key is different from computers to computers. If you can’t find it, you can refer to the instruction booklet or Google it.
2. Under the BOOT tab, choose the UEFI/BIOS Boot Mode, and change the Legacy to UEFI. Then save and exit the firmware interface.
This is about how to convert MBR(legacy) to GPT(UEFI). I hope you have a great experience with GPT disk and UEFI firmware. In Addition, with AOMEI Partition Assistant, you can also convert file system from FAT to NTFS without formatting, fill hard drive with random data, migrate OS from MBR to GPT disk or GPT to MBR.
If you are a Windows Server user, you need to use the AOMEI Partition Assistant Server Edition to convert MBR (Legacy) to GPT(UEFI).