On an MBR disk, you can only create a maximum partition size of 2TB and use only 2TB of disk space in most cases. In addition, you can only create a maximum of 4 Primary partitions on an MBR disk. Therefore, if you have a 2TB+ disk or want to create more than 4 Primary partitions, you must use a GPT disk. If you have installed Windows or saved files to an MBR disk, you can convert MBR to GPT without losing data. There are 3 common ways to convert MBR to GPT in a Windows 10 computer. This article introduces all these methods with detailed steps; select the one that fits your needs.
1. Convert MBR to GPT in Windows 10 with Disk Management
This method is only used when you can delete all partitions on the MBR disk.
As in previous versions, Windows 10 has a built-in Disk Management tool that has the options to "Convert to GPT Disk" and "Convert to MBR Disk". However, there must be no partitions on the disk. If there is even one partition, the option "Convert to GPT Disk" is grayed out in Windows 10 Disk Management.
After deleting all partitions on this disk, the convert option will be activated.
Caution: Remember to transfer files to another place before deleting. If you do not want to delete any partitions, jump to the next section.
How to convert MBR to GPT in Windows 10 with Disk Management:
- Press the Windows + X keys together and click Disk Management in the list.
- Right-click the partitions on this MBR disk and select "Delete Volume" one by one.
- Right-click the leftmost area of this disk and select "Convert to GPT Disk". In a short while, the conversion will be completed.
Obviously, it is better to convert MBR to GPT without deleting partitions for Windows 10 computers. Before starting, check if the MBR disk that you want to convert is the system disk or a data-only disk. The methods to convert these disks are different.
2. Convert MBR to GPT in Windows 10 with the MBR2GPT Command
This method is only used to convert the operating system disk from MBR to GPT.
You should pay more attention when converting a system disk to GPT. If the conversion fails, the system will be damaged, and your computer cannot boot. There are third-party tools that have the option to convert a system disk from MBR to GPT, but few can ensure that the disk will be 100% bootable after converting.
In Windows 10/11, there is a built-in MBR2GPT tool to help convert MBR to GPT without losing data. It runs from the command prompt. It is very easy and fast to convert MBR to GPT in Windows 10/11 with this command tool. However, your disk partition layout must meet the requirements. If it does not meet them, you can modify the disk partition.
Requirements to convert MBR to GPT in Windows 10 with the MBR2GPT command:
- All partitions on the MBR disk must be Primary. If there is a Logical drive, follow the method to convert it to Primary.
- There should be no more than 3 Primary partitions on this disk. If there are four or more partitions, follow the method to move some partitions to another disk.
- All partitions on this disk must be formatted with the FAT16/32 or NTFS file system.
Some people receive the error "Disk layout validation failed for disk 0" while converting a disk with MBR2GPT:
As explained above, there is a Logical drive in the first screenshot, and there are 4 partitions in both screenshots.
MBR2GPT will validate the disk partition layout before converting; if the validation fails, the conversion will not continue, so it will not cause any damage to your disk. If it converts the disk successfully, the changes cannot be undone. Remember, there is no built-in Windows tool that is able to convert GPT to MBR without losing data.
How to convert MBR to GPT in Windows 10 with the MBR2GPT command:
- Back up your system with native Windows or third-party software in case anything goes wrong.
- Press the Windows and R keys together, input cmd, and press Enter.
- In the command prompt window, input mbr2gpt /disk:0 /convert /allowFullOS and press "Enter" to execute. If your system disk is not number 0, replace it with the right one. You will see the disk number in Disk Management.
If you want to read more about MBR2GPT, input mbr2gpt /? in the command window or visit the official page.
Pay Attention to the EFI Partition
On most MBR system disks, there is a small "System Reserved" partition. After converting the disk to GPT with MBR2GPT, this partition will be removed, and a new EFI partition will be created.
MBR2GPT will first try to shrink the System Reserved partition; if there is enough free space, the EFI partition will be created to the right of this partition. If there is not enough free space, MBR2GPT will shrink the boot partition (C drive) instead, and then the EFI partition will be created behind the C drive. The problem is that Windows Disk Management cannot resize, move, or perform any other operations on the EFI partition.
If you want to place the EFI partition on the left of the C drive, extend the System Reserved partition before converting. (Extending to 2GB is absolutely enough.)
Convert without extending System Reserved partition:
Convert after extending System Reserved partition:
NIUBI Partition Editor can shrink, move, and extend the EFI partition, so you may ignore the step to extend the System Reserved partition. However, if you care about the position of the EFI partition and want to keep the C and D drives contiguous, remember to extend the partition before converting.
3. Convert a Disk with a Free MBR to GPT Converter
This method is used to convert an MBR disk to GPT without an Operating System on it.
It only requires 3 clicks to convert MBR to GPT in Windows 10/11 with NIUBI Partition Editor. It has a free edition for Windows 10/8/7/Vista/XP home computer users. Besides converting an MBR disk to GPT, this free tool helps you convert NTFS to FAT32 and convert partitions between Primary and Logical without losing data. It also helps you shrink, move, extend, and merge partitions to optimize disk space, and clone a disk or partition to migrate the Operating System and data. You can also create, delete, format, hide, defrag, wipe partitions, scan for bad sectors, etc.
How to convert MBR to GPT in Windows 10 with a free converter:
- Download NIUBI Partition Editor, right-click the leftmost area of the MBR disk, and select "Convert to GPT Disk".
- Simply click "Yes" to confirm, and a pending operation will be added to the bottom left corner.
- Click Apply on the top left to take effect, and you are done.
Watch the video to see how to convert an MBR disk to GPT with this free tool:
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