Non-Destructive MBR to GPT Conversion in Windows

Converting a Master Boot Record (MBR) disk to a GUID Partition Table (GPT) disk in Windows can be necessary for various reasons, such as overcoming the limitations of MBR disks, supporting larger disk sizes, or enabling features like Secure Boot. However, this process typically involves formatting the disk and thus erasing all data, which can be inconvenient or even disastrous if you have important data on the disk. Luckily, there are non-destructive methods available for converting an MBR disk to a GPT disk in Windows. In this tutorial, we'll walk through one such method using the built-in Windows tools.

Precautions

Before proceeding, it's essential to back up any critical data on the disk you plan to convert. While the process we'll discuss is non-destructive, there's always a risk of data loss during disk operations.
Make sure that your device supports UEFI before attempting to convert the disk. After the disk has been converted to GPT, the firmware must be reconfigured to boot in UEFI mode.

Step 1: Open Disk Management

Press Win + X on your keyboard to open the Power User menu.
Select Disk Management from the list.

Step 2: Identify the Disk

In Disk Management, locate the disk you want to convert from MBR to GPT.
Right-click on the disk and select Properties.
Go to the Volumes tab and take note of the disk's partition style. It should say Master Boot Record (MBR).

Step 3: Launch Command Prompt with Administrative Privileges

Press Win + X and select Command Prompt (Admin) from the Power User menu.

Step 4: Use the "MBR2GPT" Tool

In the Command Prompt window, type the following command:
```
mbr2gpt /validate /disk:<disk_number>
```
Replace <disk_number> with the number of the disk you noted earlier in Disk Management. This command will validate whether the disk can be converted safely without data loss.
If the validation is successful, run the following command to perform the conversion:
```
mbr2gpt /convert /disk:<disk_number> /allowfullos
```
Again, replace <disk_number> with the appropriate disk number.
Wait for the process to complete. It may take some time depending on the size of the disk and the amount of data on it.
Once the conversion is finished, close the Command Prompt window.

Step 5: Verify the Conversion

Open Disk Management again.
Right-click on the disk and select Properties.
Go to the Volumes tab and confirm that the partition style now says GUID Partition Table (GPT).

Congratulations! You've successfully converted an MBR disk to a GPT disk in Windows without losing any data. You can now take advantage of the benefits that GPT disks offer, such as support for larger disk sizes and additional features like Secure Boot. I hope you found this post helpful and informative. If you have any questions or comments, feel free to leave them below.

Thanks For Reading!

Last updated on April 15, 2024