Nowadays, hard disk size becomes larger and larger, it is common to use 2TB to 4TB HDD for personal computers, RAID array could be over 10TB in a server. If you initialzed a disk as MBR, you can use only maximum 2TB space, and have at most 4 Primary partitions. If you want to have 2TB+ partition and more than 4 Primary partitions, you must change MBR disk to GPT. Many people ask if it's possible to convert MBR to GPT without losing data. The answer is yes.
There are 3 ways to convert disk from MBR to GPT in Windows PC and Server. Disk Management has "Convert to GPT" option but you must delete all partitions on this disk first. To convert MBR disk to GPT without deleting partitions or losing any data, you need to run mbr2gpt.exe command or 3rd-party software. In this article, I'll introduce all these methods to convert MBR to GPT in Windows 10/11 and Server 2008/2012/2016/2019/2022.
How to identify if the disk is MBR or GPT?
There are two ways to identify the disk type by native Disk Management and 3rd party software. Every disk is marked as MBR or GPT by NIUBI Partition Editor, after starting it, you'll see disk type immediately and clearly.
In Disk Management:
1. Right click the front of a disk and select Properties:
2. Switch to Volume tab in the pop-up window.
How to convert system disk from MBR to GPT without data loss
Some 3rd-party software say that they can convert MBR to GPT for system disk, but few can ensure 100% system bootable. To convert a MBR system disk to GPT, it is suggested to run MBR2GPT which is provided by Microsoft. If you want to convert a data only disk to GPT, jump to next section. MBR2GPT cannot convert data disk from MBR to GPT.
MBR2GPT is a command prompt tool, it is included from Windows 10 (1703) and subsequent versions. To convert MBR to GPT in Windows 10/11 and Server 2019/2022, you can accomplish in Windows from CMD. To convert MBR to GPT in Windows Server 2008/2012/2016, you need bootable media with Windows Preinstallation Environment (Windows PE).
No matter in which Windows version, before change MBR to GPT with MBR2GPT command, your disk partition layout must meet the requirements below:
- There are no more than 3 partitions on a disk and all partitions must be Primary.
- One of the partitions is set as Active and is the system partition.
- The volume IDs can be retrieved for each volume which has a drive letter assigned.
- All partitions on this MBR disk are recognized by Windows such as FAT32/NTFS.
If your partition layout doesn't meet the requirements, you can make modification with NIUBI Partition Editor.
Common issue and corresponding solution
"Validating layout, disk sector size is: 512 bytes Disk layout validating failed for disk 0", "MBR2GPT: Conversion failed". This is the most common error message while converting MBR disk to GPT. If you received such error, check your disk partition configuration again.
On most of system disk, there are System Reserved, C: (for OS) and D drive. If all these 3 partitions are Primary, you can convert this disk successfully.
- If there's Logical drive on this disk, follow the step to convert it to Primary (without data loss).
- If there is fourth partition such as E, move it to other disk no matter it is Primary or Logical.
- If there are not supported partitions such as EXT2/3, move files to other place and delete these partitions.
1. Convert system MBR disk to GPT in Windows
If you do not know your Windows 10 version, press Windows + R together on the keyboard, type winver and press Enter.
How to convert MBR to GPT in Windows 10/11 and Windows Server 2019/2022:
- Click Windows flag on bottom left, type cmd, select Run as Administrator.
- In command prompt window, type MBR2GPT /convert /allowFullOS and press Enter.
Note: this conversion can't be undone, so before doing this, make sure your computer can boot from UEFI.
2. Convert system disk from MBR to GPT with bootable media
MBR2GPT command is not integrated in these version. You cannot convert MBR to GPT in Windows directly, but you can accomplish via a bootable media.
How to convert MBR to GPT in Windows Server 2008/2012/2016:
- Download Windows Server 2019 ISO file from Microsoft, then create bootable DVD or USB flash drive with Windows built-in or third-party tool.
- Boot from this bootable media, simply click Next in first Windows Setup window, then click Repair your computer on bottom left corner of next window.
- Click Troubleshoot in next window, then click Command Prompt.
- In the command prompt window, type cd.., press Enter, then type MBR2GPT /convert and press Enter.
How to convert MBR disk to GPT without operating system
To data only disk, it is extremely easy to convert MBR to GPT without losing data. NIUBI Partition Editor can convert disk type via several clicks.
How to convert MBR to GPT in Windows 11/10/8/7 with free converter:
- Download NIUBI Partition Editor free edition, right click the front of the MBR disk and select "Convert to GPT Disk".
- Simply click Yes to in the pop-up window to confirm, then a pending operation will be added.
- Click Apply on top left to execute, done. (All operations before clicking Apply only work in virtual mode.)
Watch the video how to convert MBR disk to GPT without losing data:
To convert data disk from MBR to GPT in Windows Server 2008/2012/2016/2019/2022, the steps are the same with before but you need the server edition. Besides convert MBR to GPT, NIUBI Partition Editor helps you convert partition between Primary and Logical, convert NTFS to FAT32 without losing data. It also helps you shrink, extend, move and merge partitions to optimize disk space usage, clone disk partition to migrate operating system and data. Defrag, wipe, hide partition and much more.