How to Change GPT Partition Style to MBR in BIOS without Losing Data?

• What is GPT format style?

• When need to change GPT partition style to MBR?

• 2 Methods to Change GPT partition style to MBR in BIOS

• Use DiskPart.exe tool (data loss)

• Use AOMEI Partition Assistant Software (no data loss)

• Summary

What is GPT format style?

Now, since Microsoft has declared that upgrading from Windows 10 to Windows 11 requires the UEFI to run successfully, users who wish to enjoy the Windows 11 system will have to choose the GPT partition style. What is GPT format style is? It is well-known that a hard disk needs to be partitioned before normal usage. And MBR (Master Boot Record) and GPT (GUID Partition able) are two partition types of the hard disk

MBR is a traditional partition structure to manage disk partitions and compatible with most systems. It uses the standard BIOS boot mode, so a BIOS-based system requires to be installed on MBR. GPT is a new standard and gradually replacing MBR. A GPT disk uses a UEFI partition table. Therefore, the UEFI-based system should be installed on a GPT disk. For more information about MBR and GPT, you can read “MBR vs GPT: Which One is Better for You?”

When need to change GPT partition style to MBR?

One of the most important reasons for which you need to convert GPT partition style to MBR might be: you are trying to install a BIOS-based Windows system on a GPT hard disk but failed, and meet the error message “Windows cannot be installed to this disk. The selected disk is of the GPT partition style.

This error message suggests that your computer is set up to boot in Legacy BIOS mode, but the hard disk you select to install OS is of GPT partition style. In Legacy BIOS, the operating system can be installed on MBR disk only, as the Legacy BIOS does not support modern GPT partition style. Thus, you will have to change GPT partition style to MBR to fix this error.

2 Methods to Change GPT partition style to MBR in BIOS

To convert GPT partition style to MBR in BIOS so as to continue to install Windows successfully,  there are two methods available. One is using Windows snap-in DiskPart.exe while another is turning to third-party software.

Method 1.  Use DiskPart.exe tool  (data loss)

This method will wipe the hard drive before changing GPT to MBR, thus you should backup anything you need in advance.

Step 1. Press the “Shift+F10” keys when you see the error message to open Command Prompt window. If that does not work, you can go back to the first screen of the installation and press “Shift+F10”.

Step 2. Type “Diskpart” in the command prompt and press “enter” to open the diskpart tool.

Step 3. Then execute the following commands in the given sequence.

• list disk: list all disks connected to your computer.

• select disk #: replace # with the disk number of your hard disk which is of GPT partition style.

• clean: this command will delete all partitions and data from the selected disk

• convert MBR: this command will change GPT partition style to MBR.

Step 4. When you see “DiskPart successfully converted selected disk to MBR format”, you can type “exit” and press enter to close the Command Prompt.

Then you can continue the Windows Setup installation. When choosing an installation type, select “Custom”. The hard disk will appear as a single area of unallocated space. Select it and click “Next”. Windows will begin the installation.

Method 2. Use AOMEI Partition Assistant Software (no data loss)

Changing GPT partition style to MBR in BIOS via DiskPart.exe will cause data loss, so here we share a great disk manager named AOMEI Partition Assistant Professional. It permits you to convert a hard disk that contains partitions from GPT to MBR, or MBR to GPT partition style in Windows 11/10/8/7 and Windows XP/Vista. Namely, you don’t have to remove partitions before conversion and take the risk of data loss.

However, you can back up the disk in case that some uncontrollable issues or improper operations damage your vital data during the conversion. You can first download the free Demo edition to experience it.

Step 1. Create a bootable USB drive (optional)

This step is necessary when you cannot boot into the computer as the Windows installation has not been finished. If you can boot into OS, skip to step 2, please.

1.1. Install and run this software on a working computer and plug an empty USB to it as well. Click "Tools" > “Make Bootable Media” and click “Next” on the pop-out window.

1.2. Choose the USB drive and click “Proceed”.

1.3. Wait for the process to finish.

1.4. Then remove the USB safely and plug it into the computer which contains the GPT disk you need to change. Enter BIOS to change boot order and boot computer from the bootable USB device.

1.5. Once login, you will see AOMEI Partition Assistant is running automatically.

Step 2. Convert GPT partition style to MBR without losing data

Now you can follow the steps to convert GPT disk to MBR while keeping inside data safe.

2.1. In the main interface of AOMEI Partition Assistant, right-click the system disk and select “Convert to MBR” or click the disk and choose "Convert to MBR" from the right column.

2.2. Click “OK” in the pop-out window.

2.3. Back to the main interface, click “Apply” and “Proceed” to commit the pending operation.

How do I change partition style from GPT to MBR? With the help of AOMEI Partition Assistant Professional, you can easily change the GPT partition style to MBR without data loss caused by partition deletion.

Tech tip: which OS can be installed on GPT disk 

Converting GPT partition style to MBR can help you get rid of “The selected disk is of the GPT partition style” error message during OS installation. However, in order to avoid this problem in the future, you might want to know which OS can be installed onto the GPT disk and boot from it successfully.

1. Windows Vista 32-bit, XP 32-bit and the early operating systems such as Windows 2000, Windows MS-DOS/NT, Windows 95/98 cannot boot from GPT disk.

2. In Windows XP 64-bit, GPT disk can be used for data storage instead of system installation.

3. All versions of Windows Vista/XP/7/8/8.1/10, Windows Server 2025/2022/2019/2016/2012 can use GPT disk to save data to, but only 64-bit editions on UEFI-based systems can be installed on GPT disk and boot from it.

Summary

This is how to change GPT partition style to MBR in BIOS via two methods. If you want to change GPT to MBR without losing data, choose AOMEI Partition Assistant Professional. It also supports converting MBR to GPT without data loss. If you want to make a conversion between MBR and GPT without deleting existing partitions in Windows Server 2019/2016/2012/2008/2003, AOMEI Partition Assistant Server can satisfy your needs.