Convert MBR to GPT Disk Windows 10

Overview of MBR and GPT

MBR and GPT are two disk styles, and they differ from each other in many aspects. MBR is short for Master Boot Record, on which you can create at most four primary partitions OR three primary partitions plus one extended partition. In this case, if you want to create more partitions, you can create more logical partitions in the extended partition. Besides, if you employ MBR disk, the maximum disk capacity Windows can make use of is 2TB.
GPT is short for GUID Partition Table, and allows users to create as many primary partitions as they like. Generally speaking, that limitation under Windows is 128. In addition, when you employ GPT disk, disks larger than 2TB can also be used fully. It is worth mentioning that system installed on GPT disk can only be booted from UEFI main board.

Why Convert MBR to GPT Disk Windows 10?

As I just mentioned above: MBR can only support 2TB disk. That means if you have a MBR disk whose total size is 3TB, then you cannot make use the of the rest 1TB disk space, which will be showed as unallocated space in windows 10, but won’t allow any operation. However, if you convert this MBR disk to GPT disk, it is able to take full use of storage space.
Note: Some old operating systems such as Windows XP 32-bit, Windows 2003 32-bit, Windows 2000, Windows NT4 won’t boot from GPT disk. Thus, if you are using these OS, it is better for you to keep it as MBR.

Change MBR to GPT W/O Data Loss

When it comes to convert MBR to GPT, you may first of all thinking of using Disk Management. Unfortunately, this will lead to data loss.
Let’s go over the steps simply:
Right click the disk to be converted, you can see “Convert to GPT Disk” is greyed out in the pop-up window, because one more step is required. You must delete all the partitions on that drive, when the whole drive becomes unallocated space, Convert to GPT Disk option is activated. (image attached)
Another solution is using Diskpart Command Line, yet the same requirement is need, you need to clean the MBR disk before you can convert it to GPT.
Thus, if you use Windows built-in tool to do this conversion, backup hard drive data first. So the next question is: can you convert MBR to GPT disk Windows 10 without data loss?
Partition Wizard Is the Top Solution to Convert MBR to GPT without Data Loss
MiniTool Partition Wizard is a powerful software for partition management. It allows users to convert MBR to GPT or vice versa without any data loss. Besides this feature, you can also use it to migrate OS to SSD, recover lost partition, and more.
Note: As there is no large drive at hand, here we just take a small drive to show how Partition Wizard help to change MBR disk to GPT.
Note: MiniTool Partition Wizard can only convert non-system disk from MBR to GPT disk. In the coming version you will be allowed to convert system disk to GPT as long as your mother board supports EFI boot mode.

Step 1: Download this software, install and launch it to load all hard drives connected to your computer. Then right click the disk you want to convert (here is disk 3) and then choose “Convert MBR Disk to GPT Disk“.
Step 2: Click “Apply” to execute this change.
Note: In case that you may need to convert a GPT disk back to MBR, you can also use Partition Wizard to carry out this operation. In this case, as long as there is some gap between every two partitions, you can convert GPT to MBR successfully even if there are many partitions.


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