Last Updated on September 8, 2026
When it comes to configuring your hard drives in Windows, you have two options for the data structure that is to be used for your disks. In most modern computers with larger drives, you will be configuring them as GPT rather than MBR.
But you may have a case where your computer’s hard drive was configured as MBR on accident or maybe even on purpose. When this happens, many people tend to wipe their drives and start over to make them use GPT. In this article, we will be showing you how to convert your Windows or other drive from MBR to GPT without losing data.
If you are running a newer version of Windows such as Windows 11 or Windows 10, there are not many, if any reasons to use a GPT disk. Here are the differences between MBR and GPT configured hard drives.
Understanding Master Boot Record (MBR)
1. Primary Partition Limits
The legacy MBR standard supports a maximum of up to 4 primary partitions. If you need more drive letters, you must create a messy extended partition. This severely limits your organizational flexibility.
2. Maximum Drive Capacity
MBR has a hard-coded maximum drive size of exactly 2TB. If you plug a modern 8TB hard drive into an MBR system, the remaining 6TB becomes completely unusable. The operating system simply cannot see the extra storage space.
3. Legacy BIOS Requirement
This older format strictly uses the Legacy BIOS system for booting up the computer. Modern motherboards are actively phasing out legacy boot support entirely. You will eventually be forced to upgrade to a newer standard.
4. Vulnerability to Corruption
MBR stores all of its critical partition information in a single location on the physical disk. This makes the entire drive incredibly vulnerable to catastrophic corruption. A single bad sector can wipe out your entire file table.
5. Operating System Compatibility
The only real benefit is that MBR remains fully compatible with older Windows versions. You need this format if you are running legacy systems like Windows XP or Windows 7. It also runs slightly slower on extremely large physical drives.
Understanding GUID Partition Table (GPT)
1. Massive Partition Support
The modern GPT standard easily supports up to 128 primary partitions natively within Windows. You do not have to mess around with extended partitions or logical drives. This gives you ultimate freedom over your storage layout.
2. Unlimited Drive Capacity
GPT can easily handle massive hard drives far larger than the old 2TB limit. It supports theoretical capacities that stretch into the zettabytes. You need this standard for modern high-capacity solid state drives.
3. Modern UEFI Boot Mode
This layout requires the modern UEFI boot mode to function properly on modern systems. It integrates deeply with Secure Boot to protect your computer from rootkits. This is the absolute standard for all hardware manufactured today.
4. Redundancy and Recovery
GPT stores critical partition data in multiple locations across the physical disk. This drastically improves data recovery efforts and reduces total corruption risks. The system can automatically repair itself if the primary header gets damaged.
5. Windows 11 Requirements
This format is strictly required for modern Windows 10 and Windows 11 installations running on UEFI firmware. Microsoft mandates this architecture for all new operating system upgrades. It also offers significantly better performance and overall efficiency.
Convert Your Windows Drive from MBR to GPT
For our first example, we will be converting the primary Windows system drive from MBR to GPT without losing any data. When doing any procedure like this, always be sure to do a full backup of your important files just in case something goes wrong. We will be running a specific command to do the conversion safely.
You can run this process from within Windows, from the Windows PE environment, or even from the Windows recovery command prompt. We will be doing our MBR to GPT conversion directly from within the active Windows desktop. The image below shows that our C drive is currently configured as MBR.
The image below shows that our C drive is configured as MBR since there is an option to convert it to GPT. The option is greyed out so we cannot do it from the Windows Disk Management tool.
1. Open an Administrative Command Prompt
We will be using the powerful mbr2gpt command to convert our system disk to GPT. The mbr2gpt command is built directly into Windows so there is absolutely nothing to download or configure. To start the process, open an administrative command prompt by typing cmd in the Windows taskbar search box and choosing Run as administrator.
2. Validate the Disk Layout
The first command we will be running is used to validate that we can actually perform the MBR to GPT conversion on this specific drive. You can copy and paste mbr2gpt.exe /allowFullOS /validate /disk:0 directly into the command prompt. If your Windows disk is not disk 0 as shown in Disk Management, you will need to change that number in the command string.
3. Execute the Conversion Command
Now that the initial validation has completed successfully, we will run the next command to perform the actual conversion. Type mbr2gpt.exe /allowFullOS /convert /disk:0 into the terminal and press Enter. This process rewrites the partition table while leaving your personal files completely untouched.
4. Switch Your Firmware to UEFI
After the process has been completed, you should get a message stating that before the new system can boot properly you need to switch the firmware to boot to UEFI mode. If your computer is set up to use a legacy BIOS, you will need to go into the motherboard settings and change it to UEFI immediately. You may want to make sure your computer actually has a UEFI setting before starting this entire procedure.
5. Verify the GPT Conversion
We will now shut down the computer completely and change the boot options to UEFI. Restart the machine and log back into your Windows profile. Open Disk Management and right-click the drive to verify the status. It should now say Convert to MBR, telling us that it is successfully using the GPT architecture.
Convert a Non System Drive from MBR to GPT
Converting a non-system drive from MBR to GPT is an easier process than doing so with your active Windows drive. As you can see in the image below, our other hard drive is configured as MBR. We know this because we have the greyed out option that says Convert to GPT Disk inside the native Windows tool.
1. Download NIUBI Partition Editor
This time, we will be using the free NIUBI Partition Editor software to convert this secondary drive to GPT. NIUBI comes in a standard installable version and a convenient portable version. Download the application and launch it on your desktop.
2. Locate the Target Drive
Once you run the NIUBI software, you will see an interface that looks highly similar to Disk Management but with many more features. As you can see, Disk 1 shows that it is currently configured as MBR. Disk 0 now shows that it is configured as GPT from our previous steps.
3. Select the Conversion Option
We will now right-click directly on Disk 1 to open the context menu. Choose the Convert MBR to GPT option from the available list of actions. This stages the partition modification in the software queue
4. Confirm the Operation
A small prompt will appear on your screen asking for confirmation. We will then have to click on the Yes button to confirm the conversion request. The software will not execute the change until you apply the pending operations.
Any time you make a change in NIUBI Partition Editor, you will need to click the Apply button for the changes to take effect.
5. Apply the Pending Changes
Any time you make a change in NIUBI Partition Editor, you will need to click the Apply button at the top left for the changes to take effect. The program will process the sector changes rapidly. We do not need to reboot the computer or change any BIOS settings when converting a non-system drive.
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