3 Free MBR to GPT Converter for Windows 11/10/8/7 (No Data Loss)

🧐 This article was fully reviewed and updated for Windows 11/10 in April 2026.

As we all know, when setting up a new disk on a Windows computer, we will receive a message saying “You must initialize a disk before Logical Disk Manager can access it”.That is to say, we need to initialize the new hard drive to either MBR or GPT before using it for data storage.

Converting a disk from MBR (Master Boot Record) to GPT (GUID Partition Table) used to be a risky task that required wiping all your data. Today, depending on your specific situation, it can be done easily and safely.

In this comprehensive guide, we will break down the exact scenarios where you need to convert to GPT, show you the built-in Windows tools, and introduce the best free and advanced MBR to GPT converters to get the job done without losing a single file.

MBR vs. GPT: Basic information about MBR and GPT

MBR (Master Boot Record) and GPT (GUID Partition Table) are two different partition styles for hard disks. MBR is an old hard disk style to manage the partitions while GPT is the latest standard for disk partition management. The main differences between MBR and GPT are disk size, partition number limitations, etc.

Quick Comparison Table (MBR vs. GPT)

Feature	MBR (Master Boot Record)	GPT (GUID Partition Table)
Max Disk Capacity	2 TB	9.4 ZB (Almost unlimited)
Max Primary Partitions	4	128 (on Windows)
Boot Mode	Legacy BIOS	UEFI
OS Compatibility	Older systems (Windows 7/8)	Modern systems (Windows 10/11)
Data Security	Stores boot data in one place	Stores backups across the disk

If you are initializing a brand-new, empty hard drive, you might need a dedicated tool to set the correct partition scheme right from the start. Check out our recommendations for the Best GPT Format Tools.

4 Common Scenarios: When Converting MBR to GPT via Free MBR to GPT Converter?

Users usually realize they need to convert their disk from MBR to GPT when they encounter one of these four specific scenarios. We can divide them into two categories: Data Disk issues and System Disk issues.

Category A: Need to  Convert Data Disk to GPT Scenarios (Storage Drives)

• Scenario 1: You bought a large hard drive (over 2TB), but your computer only lets you use 2TB. The rest of the space is marked as "Unallocated" and cannot be used.

• Scenario 2: You need to create more than 4 primary partitions to store different types of files (e.g., work, personal, games, backups), but MBR restricts you to only 4.

If your disk is purely for storage (no Windows OS installed on it), as the scenarios show, the conversion is relatively simple. Here are three FREE ways to do it.

Method 1: Use Disk Management (Causes Data Loss)

Windows has a built-in tool called Disk Management. However, it can only convert an empty disk. Disk Management is a Windows native tool for users to perform some basic disk partition management tasks, such as formatting/creating/deleting/extending/shrinking partitions. To free convert MBR disk to GPT disk via this tool, you need to first delete all partitions on the target MBR disk to make it an unallocated disk space, then you can complete this conversion.

So, if you want to convert the disk to GPT without data loss, you had better back up the MBR disk before doing as below：

1. Right-click “My Computer/This PC” -->”Manage”-->”Disk Management”.

2. Right-click on each partition on the disk you want to convert and select "Delete Volume" to clean the disk.

Step 3. Right-click on the target disk, and select "Convert to GPT Disk".

Then follow the hints to finish converting MBR to GPT. It won’t take a long time to finish this operation. After this, you can restore the data you backed up beforehand to this GPT disk.

Method 2: Run DiskPart in CMD (Causes Data Loss)

Similar to Disk Management, Diskpart is also a Windows built-in tool for users to manage their disk partition. It also only supports converting an empty disk to GPT, so you need to delete all volumes on the disk before using this free MBR to GPT converter.

Step 1. Press Win+R together on your keyboard, type cmd in the Run dialogue and press Enter to open the Command Prompt window.

Step 2. In the Command Prompt window, type diskpart and hit on Enter to launch the Diskpart tool. Then run the following commands in turn and press Enter after each one.

• list disk
• select disk #
• clean
• convert gpt

Step 3. After that, you can type "exit" and press Enter to close this window. Then you can see it is converted to GPT style in Disk Management.

Method 3: Use AOMEI Partition Assistant (Free & No Data Loss)

The first two free MBR to GPT convert tools require you to delete every existing partition on the MBR disk, which will cause data loss. If you want to convert MBR to GPT without deleting volume and losing data, the free partition manager - AOMEI Partition Assistant can satisfy your requirements best.

It is not only a free MBR to GPT converter but also a free GPT to MBR converter. Therefore, no matter whether you want to convert MBR to GPT, or GPT to MBR in Windows 11/10/8/7, it can ensure a successful conversion by keeping all partitions safe in the target disk.

Step 1. Download and open AOMEI Partition Assistant.

Step 2. Right-click your MBR data disk and choose "Convert to GPT".

Step 3. Click OK, and then hit "Apply" in the top left corner.

Within seconds, your 4TB drive or your multi-partition layout will be fully unlocked, with all your original files perfectly intact.

Category B: Convert System Disk to GPT Scenarios (Boot Drives)

• Scenario 3: While trying to install Windows, you get an error message saying, "Windows cannot be installed to this disk. The selected disk has an MBR partition table."

• Scenario 4: You are trying to upgrade from Windows 10 to Windows 11 via "Check for Update," but the PC Health Check app says your PC must support UEFI and Secure Boot (which requires a GPT boot disk).

Method 1: Using Windows Built-in MBR2GPT Tool (Via Bootable USB)

Microsoft provides a command-line tool called MBR2GPT specifically for converting system disks without deleting data. You typically need to use a Windows Installation USB to enter the advanced CMD environment to convert MBR to GPT using CMD without data loss.

Tips:
● The USB drive should be at least 4GB of storage (for a 32-bit operating system) or at least 8GB (for a 64-bit system).
● Back up files you have stored on the USB drive because the drive will be formatted during this process and all files on it will be erased.

Part 1: Create Windows installation USB

Step 1. Download MediaCreationTool and run it as an administrator.

Step 2. Select ”Accept” in the license terms screen.

Step 3. Select “Create installation media for another PC”, and then select Next.

Step 4. Choose the language, edition, and architecture (64-bit or 32-bit) for Windows 10.

Step 5. Choose ”USB flash drive” and click “Next”.

Step 6. Choose your prepared USB drive from the list, then ”Next”.

Step 7. Once done, you can use this USB to convert MBR to GPT on your system disk in WinPE.

Part 2. Use MBR2GPT commands to convert the system disk to GPT

Step 1. Plug in a Windows installation USB, and start to install Windows. Meanwhile, press Shift + F10 to open the Command Prompt window. 

Step 2. Type in “mbr2gpt /convert /disk 0 /allowfullos” if there is more than 1 disk on the computer, and 0 stands for the system disk number.

While MBR2GPT is free, it is known for being extremely sensitive. Users frequently encounter errors that stop the conversion midway. The most famous one is when the tool fails to identify where your Windows is installed, shown as "Cannot find OS Partition(s) for disk 0".

Method 2. Use Professional System Disk MBR to GPT Converter (Data Safe)

AOMEI Partition Assistant also supports system disk MBR GPT conversion. Still, AOMEI Partition Assistant Standard only supports converting data disk between MBR and GPT styles without deleting partitions and the capacity of the data disk should be within 2TB. To convert a data disk beyond 2TB or convert a boot disk between MBR and GPT, please upgrade to the Professional Edition.

To convert the system disk, if your Windows is running well, you can directly convert your system disk, but if your Windows can't boot as well and you need to convert your system disk to GPT, you'll need to find a running Windows to make a bootable AOMEI Partition Assistant USB to boot into the software at first.

Here are how to make a bootable USB via AOMEI Partition Assistant

Step 1. Connect the USB drive to a working Windows computer, install and run AOMEI Partition Assistant Professional. Click “Make Bootable Media” and hit on “Next” to proceed.

Step 2. Choose the right USB drive under “USB Boot Device” and click “Proceed”.

Step 3. Then you will be told the USB will be formatted, please back up important data. If you have done that, click “Yes”.

Then we can start to convert GPT to MBR without losing data having no access to OS.

Step 4. Use the bootable USB to boot your computer by entering BIOS. Then you'll see the main interface of AOMEI Partition Assistant. Then, you can follow the same operation as converting a data disk to GPT to convert your system disk. 

Then you need to restart your PC and go to BIOS to change the boot mode from Legacy to UEFI mode.

Notes:
If you want to convert GPT to MBR or MBR to GPT in Server 2025/2022/2019/2016/2012, you can try AOMEI Partition Assistant Server.

Conclusion

Compared with Windows native Disk Management and Diskpart, AOMEI Partition Assistant Standard is a better free MBR to GPT converter. Besides, it can handle many other difficult disk management operations, such as cloning MBR disk to GPT, migrating OS drive to SSD or HDD, moving apps or folders to another drive, testing hard drive speed, and more.

FAQs about MBR to GPT converter

1. Are there any risks involved in converting MBR to GPT?
While the conversion process is generally safe, there is always a slight risk of data loss if something goes wrong during the conversion. It's important to back up your data before attempting any partition-style conversion.

2. Is it better to use MBR or GPT?
It is determined by the amount of disk space available. GPT is preferable to MBR if your hard drive is greater than 2TB. If your computer is BIOS-based, select MBR for the system disk; if you use a disk less than 2TB for data storage, both GPT and MBR are acceptable.

3. Will converting to GPT delete my Windows OS?
If you use Disk Management or the basic DiskPart clean command, yes, it will erase everything including Windows. However, if you use the Windows MBR2GPT tool or AOMEI Partition Assistant Professional, your Windows OS and personal files will remain safe.

4. Can I convert MBR to GPT without reinstalling the operating system?
Yes! If your PC cannot boot into Windows (Scenario 3), you can create a Bootable USB using AOMEI Partition Assistant on another working computer. Plug that USB into the broken PC, boot from it, and you can convert the disk to GPT easily from the AOMEI interface.

5. How do I know if my disk is MBR or GPT?
Right-click the Start menu, open Disk Management, right-click your disk (e.g., Disk 0) on the left side, select Properties, and go to the Volumes tab. It will display the "Partition style" as either Master Boot Record (MBR) or GUID Partition Table (GPT).