How to Convert MBR to GPT Without Losing Data or Reinstalling OS With Fix for Validation Failures

This video will show you how to convert disk scheme from MBR to a GUID Partition Table GPT without losing data or reinstalling OS in windows 10 and windows 11 computers.

For more and updated details, read this topic in our blog:

This method will allow you to switch firmware from Basic Input/Output System (BIOS) to Unified Extensible Firmware Interface (UEFI).
UEFI mode has many advantages over Legacy mode, such as secure boot, faster startup, bypassing MBR disk limit of a 2 Terabytes as maximum disk size with four primary partitions as maximum numbers, in addition, UEFI will allow you updating to or installing windows 11 in your computer.

HOW TO REPAIR WINDOWS RECOVERY ENVIRONEMNT WINRE AND TO UPDATE REAGENT.XML:

IMPORTANT NOTES:
Before attempting to convert the disk to GPT, make sure that your computer supports UEFI because the conversion process can’t be reversed back without losing data.
Once the disk gets converted to GPT disk scheme, the BIOS firmware must be reconfigured to boot in UEFI mode.
Windows Recovery Environment should be enabled, so you can recover your system if you advanced into a trouble.

FIRST: How to check if your computer supports UEFI:
The List of hot keys to enter Boot Menu for different brands including laptops and desktops:
- Acer: F12, F9 or Esc.
- Asus: Esc. or F8
- Compaq: F9 or Esc.
- Dell: F12
- Fujitsu: F12
- Hp: Esc. or F9
- Lenovo: F12, F8, F10, Novo Button or Fn+F11
- MSI: F11
- Razer Blade: F12
- Samsung: F12 or F2
- Sony: Assist Button, Esc or F11
- Toshiba: F12

SECOND: How to check if your disk has a GPT or MBR:

THIRD: how to convert the disk into GPT:
Type CMD into search box
Right click on Command prompt and select, Run as administrator
Execute this command to convert the disk into GPT:
MBR2GPT /CONVERT /ALLOWFULLOS
If you are trying that from Windows Recovery Environment (WinRE) or preinstallation environments, you have to change the CMD path to System32 folder using this command:
CD /D D:\WINDOWS\SYSTEM32
Then execute the command without /ALLOWFULLOS option
Otherwise, the command will fail with this error message
MBR2GPT is Not Recognized as internal or external command.
If the conversion failed with this or another error message, “Disk layout validation failed for disk 0” then you have to check the followings:
The disk is currently having an MBR scheme
The Bitlocker is disabled on the disk.
There are no more than 3 primary partitions on the disk with at least 1-megabyte free space in all partitions
There is no any extended or logical partition on the disk
The system partition is set as active and contains valid BCD file

Execute LIST VOL to show available volumes
Select windows volume using this command:
SEL VOL 2
Type LIST PART then press Enter to show available partitions

Select the partition to be deleted using this command:
SEL PART 4
Delete the selected partition using this command:
DELETE PARTITION

Execute EXIT command to close the DISKPART
Press up arrow key from keyboard to explore previous commands, then execute MBR2GPT again to start conversion.
Now power off the computer to change BIOS settings.

FOURTH: How to change settings of BIOS firmware to boot in UEFI mode:
Power on the PC then Boot into BIOS menu as seen in first part of the video.
Navigate to Boot option and change Boot mode to UEFI.
Unlike the disk ordering in the boot list of MBR or legacy scheme, the GPT scheme has a new boot option called Windows Boot Manager.
You may need to change the SATA Controller mode to AHCI.

Navigate to Exit panel and click on Exit Saving Changes option to boot into windows.
The first boot will take longer time, so be patient.

To show deleted partition, right click on Start icon then select, Disk management.
Right click on Unallocated space and select, New Simple Volume option.
Change the Size of new Volume if you want, otherwise, click next to take all available size.
Change the assigned letter if you want, otherwise click on Next to continue.
Move the files and folders back to the new volume.

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[georgioskatsillis]

This video was a life saver. Finallly since Windows 11 came out, my computer is ready for it! Before… mbr2gpt wouldn't make the conversion of my system disk and it turns out because of an extra partition. With the help of the video i could delete it and convert my system disk to gpt.

[alinked]

Man, the only person who tells us all the problems which prevent from verifying\converting and their solutions. Very helpful! Thank you!

[nickgmerq]

Bro, 2 months trying to change that option cuz i want to play valorant, you are the only one that do it, i love you, thank you for all

[Vicky-zduv]

Thank you for your tutorial, it worked well for me. Also aomei is nice to convert the disk.

[felicitybrown]

This is an informative tutorial, and I also fixed by converting from mbr to gpt with ao mei partition this one is nice.

[princeofdarkness]

I just keep getting 'cannot find os partition(s) for disk 0 mbr2gpt'

MB is AS rock B450 Pro 4 with update to UEFI....(on starting PC it has always given option to press F2 to enter UEFI settings)

[lauryn]

what tools did you use, I use partition assistant it's easier than command line

[rubyzeng]

will not work for my disk then i convert with aomei partition that is nice to manage

[bvvmtsc]

Hi ! I’m from thailand,

I’ve seen many others video but not work until I meet your video

This is the great video !!!

I’m very happy from your help video can made me fix my laptop mbr disk to gpt disk fail because my disk have more than 3 partitions

Thank you very much

[danielfennock]

I converted with aomei partition assistant because diskpart is not working for system disk

[javadhamreh]

When you got all the questions in advance and all the answers too 😂

[danielfennock]

I met this error and I just converted the disk with partition assistant and it fixed the problem

[xxhomie]

can you help me with a question, can I move the os to ssd but leave the data on hdd?

[aaryanverma]

Words can't describe how thankfull I am

[Vicky-zduv]

So I converted the disk and plan to move the os to ssd so I can boot from it and save other data on hdd, I cloned successfully with partition assistant.

[jordanrose]

Thank you so much for this video! I ran the command using command prompt and it worked great!

[JoseGonzalez-cggs]

This was quick and error free. I'm now finally installing Windows 11, thank you so much!

[Noor_ul_Ameen]

Please ans my question if I put this command after all the steps mbr2gpt /convert /allowfullows
It's showing invalid argument-/allowfullows
Please help me 😫😫

[mohammed_hood]

This actually worked, this is amazing finally after alot of videos this video fixed everything thank youuuu so

[wenn]

But delete partiton will cause data loss, ao mei partition will not cause data loss while converting.