MBR stands for Master Boot Record, the most common partition style that is often used in a Windows system. It supports both types of BIOS: Legacy and UEFI. However, due to the lack of storage capacity, users gradually switched to using GPT instead of MBR.
GPT stands for GUID Partition Table, which provides more options than the MBR partition style. The downside of MBR is that it only supports four partition table entries. That said, if you want to create more partitions, you will need to create a secondary structure, called an extended partition.
So, if you use a hard drive that has a storage capacity of more than 2TB, you will need to use the GPT partition style. Otherwise, the rest of your disk space won’t be used. This partition style also doesn’t have any limitations regarding the numbers of partitions that you can create on a GPT hard drive.
The structure of the GPT format:
How To Convert MBR To GPT Without Losing Data In Windows 10
Although switching from MBR to GPT is a good move, many users still worry about losing data when doing so. Fortunately, Microsoft has released an official tool that will assist you in converting from the MBR partition style to GPT without losing any data.
Use MBR2GTP To Convert MBR To GPT Without Losing Data In Windows 10
With the release of the Windows 10 Creators Update, Microsoft brought to users a new utility called MBR2GPT Disk Conversion. This tool will help you to switch from legacy BIOS to UEFI BIOS style quicker and more securely, without having to move all the data off the hard disk.
The MBR2GPT Disk Conversion is a safe & non-destructive command line tool, which will allow you to convert from MBR to the GPT partition style without modifying data on your disk. Originally designed for the Windows Preinstallation Environment (WinPE) environment, it’s now available to use as a built-in command line in the Creators Update. That said, your Windows 10 PC must be updated to version 1703 (which is known as the Creators Update), or later to run this utility.
MBR2GPT.exe is located in C:\Windows\System32 folder, which can be run from WinPE or directly within the Windows 10 via Command Prompt. It can also be used to convert MBR disks that are encrypted with BitLocker. Furthermore, you can use MBR2GPT to convert a Windows 10 operating system from MBR to GPT as an offline conversion when it was installed on another hard drive. That said, you can unplug a hard disk of another Windows 10 PC, plug into your computer and then perform the MBR to GPT conversion without having any issues.
Note: You can’t convert Windows 7, Windows 8, or 8.1 disks from MBR to GPT. Instead, you need to upgrade those to Windows 10 first and then perform the conversion.
To use MBR2GPT, press Windows + X and then choose Command Prompt (Admin) to open it as an administrator user.
The syntax of MBR2GPT’s command is:
MBR2GPT /validate /disk:[diskNumber] /logs:[logDirectory] /map:[source] /allowFullOS
Use this syntax to perform the disk validation steps and get the report whether the disk can be converted or not.
MBR2GPT /convert /disk:[diskNumber] /logs:[logDirectory] /map:[source] /allowFullOS
Run the disk validation and then perform the MBR to GPT conversion if all validation tests have been passed.
By default, the MBR2GPT.exe utility is blocked from running unless it’s in the WinPE environment. Adding /allowFullOS will override this restriction and allow us to perform the disk conversion while running in Windows 10.
For any questions regarding using the MBR2GPT, feel free to ask by leaving your comment below, or read this official document from Microsoft.com