The GUID Partition Table (GPT) was introduced as a part of the Unified Extensible Firmware Interface (UEFI). GPT provides more options than the traditional MBR partitioning method that is common in Windows 10/8/7 PCs. If you have a large-sized Hard Drive, then you could want to convert MBR to GPT. This is because MBR disks support only four partition table entries. If one wants more partitions, one needs to create a secondary structure known as an extended partition.
So for any hard drive over 2TB, we need to use a GPT partition style. If you have a disk larger than 2TB size, the rest of the disk space will not be used unless you convert it to GPT. The number of partitions on a GPT disk is not constrained by temporary schemes, such as container partitions defined by the MBR Extended Boot Record (EBR).
Here is an image of the basic disk that explains the GPT format.
Remember there will also protective MBR area for backward compatibility. For more information on GPT, refer to chapter 5 of Unified Extensible Firmware Interface (UEFI) specification (version 2.3) defines the GPT format.
Convert MBR to GPT without Data Loss
One of the main challenges that we face while converting MBR to GPT is that conversion is possible from MBR to GPT only if there are no partitions or volumes present in the disk – which makes it impossible to convert without data loss. I still don’t know why Microsoft hasn’t offered a simpler solution to this problem.
How do I change from MBR to GPT in Windows 10?
Luckily there are some of these solutions that will help you in converting MBR to GPT without data loss.
- Convert MBR to GPT using Diskpart
- Convert MBR to GPT without data loss using Gptgen
- Convert MBR to GPT without losing data using a third-party freeware
- Use MBR2GPT Disk Conversion Tool.
Before you start, it is, in any case, always a good idea to BACK UP YOUR DATA first to a safe place.
1. Convert MBR to GPT using Diskpart
Backup all your data and then use the DISKPART command.
- Open command prompt, type DISKPART, and press Enter
- Then type in list disk (Note down the number of the disk that you want to convert to GPT)
- Then type in select disk number of disk
- Finally, type in convert gpt.
2. Convert MBR to GPT without data loss using Gptgen
You can convert MBR to GPT without losing data – using a command-line utility called gptgen.
Gptgen is a tool designed to non-destructively convert hard disks partitioned in the common, “MSDOS-style” MBR scheme (including extended partitions) to use a GUID partition table (GPT).
It’s a pervasive tool but a bit complicated to run. According to the tool’s ‘read me’ file, the syntax of the tool is “gptgen [-w] \\.\physicaldriveX”,
- Here X is the drive number reported by the Disk Management console or the “list disk” command of the DISKPART utility.
- The -w switch makes gptgen write the generated GUID partition tables to the disk – otherwise, the primary table will be written to a file named “primary.img“, and the secondary table to “secondary.img“, in the directory that the program was invoked from.
- You can then use dd to write the tables to the disk.
3. Convert MBR to GPT without losing data using Partition Assistant
The last method is using a tool called AOMEI Partition Assistant Lite Edition. It’s a free multifunction partition management software. This tool’s feature can help you convert a disk with data into GPT or MBR style without data loss.
NOTE: It appears that now the free version of Partition Assistant does not allow converting MBR to GPT.
To convert a disk to MBR/GPT disk:
- Select the disk to convert;
- Right-click the disk and select Convert to GPT/MBR Disk;
- Confirm your operation by clicking “OK” to continue;
- Click Apply button on the toolbar to commit the changes.
4. Use MBR2GPT Disk Conversion Tool
To convert MBR to GPT using the built-in MBR2GPT.exe tool:
Boot into Advanced Startup Options screen > Troubleshoot > Advanced options > Command Prompt.
Execute the following command to validate that the drive meets the requirements:
mbr2gpt /validate
Execute the following command to convert the drive from MBR to GPT:
mbr2gpt /convert
Restart your computer.
Do note that MBR2GPT can only be used from the Windows Preinstallation Environment. To use it from your Desktop, you have to use /allowFullOS to override.
Read more about the new MBR2GPT Disk Conversion Tool in Windows 10. Using this built-in tool, you can safely and non-destructively convert a Windows 10 computer from legacy BIOS to UEFI disk partitioning.
TIP: Take a look at this post which covers various MBR2GPT failed errors on Windows 11/10, explaining the causes and providing step-by-step solutions for each situation.
- MBR2GPT disk layout validation failed
- MBR2GPT cannot find OS partition
- MBR2GPT cannot find room for the EFI system partition
- MBR2GPT non system disk
- MBR2GPT cannot install new boot files
How Can I Convert MBR to GPT without Reinstalling Windows?
To convert MBR to GPT without reinstalling Windows, you must use a third-party software, such as AOMEI Partition Assistant. Once the conversion is done, you will have to enable UEFI boot mode before booting your computer, or else your computer might fail to boot. Windows Disk Management doesn’t offer any way to convert without loss of data.
Related: How to convert Hard Disk or Partition to NTFS format in Windows
Should I Use MBR or GPT for Windows 10?
GPT is better than MBR when it comes to setting up a drive. GPT is more modern and a robust standard that all computers are moving toward. If you are looking for compatibility with old systems, then you may have to continue with MBR.
Read: How to Prevent Data Corruption in Windows computers
Is it Worth Converting MBR to GPT?
If you are moving to a modern system, then yes, it is worth it. The file system offers more security, supports a larger partition size and disk size using disk to GPT disk. However, Windows doesn’t offer a conversion without a format or data loss of the primary partitions, so it’s better to use third-party software that can do it.
Can MBR work with UEFI?
Yes, UEFI supports backward compatibility using the legacy mode, but it is possible that the modern OS, such as Windows 11, may not support MBR anymore. So while it may work with the old system, it will not work with the future Windows versions.
What is the Limitation of MBR vs. UEFI?
If you plan to use a large disk size, i.e., more than 2.2 TB of disk space, MBR will not work because the file system doesn’t support it based on its design. MBR uses 32-Bit values to describe the start and end and hence gets limited at 2.2 TB. Since UEFI uses 64-Bit, it can support up to 9.4 zettabytes (ZB) of disk space; hence there is a huge advantage of GPT disks.
If you know of any other method to safely convert MBR to GPT conversion, please share it with us under the comments session.
Can That work if the computer Still use Bios ?
Yes it should.
I want to convert my HDD without data loss and the HDD already has windows installed in it. my question is how will i boot back to windows without formatting my HDD
I am using ssd and cant convert it gives me an error
Hi, I am installing windows 8, i have a similar situation as the above screenshot. Can I right click on C: and convert mbr to gpt. Are you 100% sure that the data in E and F drive will be safe? Just a confirmation as the data is very important. If anyone has done it, please care to reply. Waiting
Unfortunately AOMEI Partition Assistant only supports to convert non-system disk (data disk) from MBR to GPT or GPT to MBR without losing data, does not support for converting system disk between MBR and GPT
Only for non-boot disks, BIOS-based (i.e., non-EUFI systems), cannot boot from a GPT disk (but this article focuses on converting non-boot disks only anyway).
Is it possible to use AMOEI Partition Assistant as follows?
Clone Boot Drive C, now D
Boot from D
Convert original Boot Drive C to GPT
Remove Boot Drive D
Boot from original Boot Drive C which should now be in GPT format.
I need more space on my boot C (2 Tb), which is MBR, and by converting to GPT I can move to a 4Tb boot
I haven’t tested this myself so I really can’t comment. But when a good backup you can proceed. Let us know how to goes.
For process 1 I had to use “clean” command after selecting the disk, otherwise it wouldn’t convert. Now I have winsdows installing!
I finally had to delete the “freedos” installed in my partition because neither of the “convert without data loss” solutions worked.
After converting my hard disk to gpt using amoei i got a problem. Which says please enter a boot disk what to do
1) Boot with Recovery mode i.e Press F11 when the system is booting
2) Click on Advanced Option
3) Select the command prompt option
4) Type diskpart and press enter
5) Type select disk # and press enter.
NOTE: Substitute # with the actual disk number that you want to convert to a mbr disk. For example, select disk 1
6) Type CLEAN and press enter
7) Type CONVERT MBR and Press enter
8) Type CREATE PARTITION PRIMARY SIZE=50000
NOTE: (The size is in MB, so enter the amount that you want to use for your system partition.)
9) Type FORMAT FS NTFS LABEL “SYSTEM” QUICK
10) Type exit and press enter
11) Insert your bootable DVD and Reinstall your windows
Remember that in this case all data will be erased. If there are important data, they can be copied via the console using the copy / robocopy / xcopy
Hello,
I have 2 disks in my system.
Disk 1 ( MBR )
I have
driver D: 75 GB ( used 7 GB )
driver E : 129 GB ( Used 94 GB )
driver f : 129 GB ( Used 58 GB )
driver G: 129 GB (used 100GB )
DISK 2 ( MBR )
driver C: 30 GB ( Used 29 GB )
I want all this drivers in single disc.. how can i do that
In GPT it’s still NTFS? whats the difference for small disks?
The difference is the partition layout is using GPT instead of a MBR. GPT has nothing to do with the type of format(s) used…
Thank you
I setup a new GBT 3TB drive, cloned an existing 1TB of data across (which took a reasonable amount of time) only to discover the original was using MBR and carryied the partition info over leaving my new drive at 2TB max. Just wanted to say a big thank you as most forums had suggested wiping and starting again with a straight file->file copy between drives. I used the AOMIE Partition Lite program mentioned in your post and got my 3BT drive back to GBT in a couple of minutes with a restart and extended it back to 3TB. Thanks!!
hello shyam
please i have any HDD from my DVR that has recording inside and i want to view the past images on my system. what i did i got an external case and fix the drive in it becuse the HDD does not have a located part on it so the system is not seen it in my computer but can be seen in Disk management so what can i do? if i convert from basic to mbr will my data be lost or not
in the method 1 ,,, to clean all data which command should i use ???
Does Method 2 also clone the partitions unreadable by Windows? I need to convert a disk which already has NTFS and EXT4 partitions.
I’ve used the gdisk command line utility to convert MPT disks to GPT before. It’s open source and available for many oses.
I have a question regarding MBR conversion to GTP conversion, even though i have different hard disk partition it display in the number only one disk0. But i want to format the hard disk only in the partion D to be the windows 8, could you please tell me how you do that without deleting the data ?
I cloned nearly full MBR 1TB system drive to a new 3TB. I have similar situation like you. But mine is system drive. According to their website, AOMIE dosn’t support for booting drive. Any solution for me? I need to convert MBR to GPT and maximize partition in my new 3TB.
You need BIOS with RAID support.
The professional edition works without having to delete anything. All you need is a reboot
great stuff – your mbr to gpt convertion tips saved me from trashing a used 4tb hdd i could not get past 2tb to partition the remaining 1.7tb despite my bios settings. so now thanks to you all 3.7tb are usable.
What wrong am I doing pls advice Thank you in advance.
E:IOSgptgen-1.1>gptgen [-w] \.physicaldrive1
gptgen: Partition table converter v1.1
Usage: gptgen []
where device_path is the full path to the device file,
e.g.\.physicaldrive0.
Available arguments (no “-wm”-style argument combining support):
-b , –backup : write a backup of the original MBR to
-c nnn, –count nnn: build a GPT containing nnn entries (default=128)
-h, –help, –usage: display this help message
-k, –keep-going: don’t ask user if a boot partition is found
-m, –keepmbr: keep the existing MBR, don’t write a protective MBR
-w, –write: write directly to the disk, not to separate files
gptgen: Too many arguments (3).
E:IOSgptgen-1.1>
I have 2 partation 1 is 400 GB and another is 300 GB i want to format the 400 GB and convernt form GTP to NTFS but only 400 GB driver not and 300 GB driver how i do plz help
I have 2 partition C is 400 GB and another is 300 GB i format the C 400 GB and now i want to convert form GTP to NTFS but with out format the 300 GB drive with out losing data
This is actually not correct, at least as of now. It is correct that the free version cannot do this but one can acquire the “Portable” version of the software from an unnamed peer to peer sharing site that is pre-activated and that worked like a charm for me.
hii.. i m using aomei software tool to convert gpt to mbr….
but after whole processing, modification is same as before..
i have used many tools but many shows same behave.
please guied me..
hi, i have veri serious problem and need your help :( i have hdd with gpt partition style, i use AOMEI PARTITION ASISTENT to convert gpt to mbr… after convertation my files from d disk lost :( :( how can i recover this files??? and why this partition asistant delete this files???? halp please :(
sir, but it doesnt support if disk has more than 4 partitions to convert gpt to mbr. four of my partitions related to system recovery etc… another one is c drive…. what should i do?
Partition Assistant worked better than expected, now I can expand my 3Tb drive : D
free version of Partition Assistant does NOT allow converting MBR to GPT – you have to upgrade.
Now the Pro Version is free.
Careful with gptgen, it will unmount the drive and when remounting it, it may not assign the previous drive letter if it was a custom one (like X:)
It was easy using Paragon’s Partition Manager
Shyam,
Your blog at captaindbg.com seems to have been suspended. :-(
Thank you very much.
Can this be done in a BIOS pc and still have windows boot
Please help! I have erased my os and now i cannot reinstall it because the selected disk is of the GPT partition style. I have 2 partitions, 1 that is empty for the os to be installed and the 2nd that is full with my data. How should i proceed to install os without erasing my data? Thank you.
can you give a hint asto wich p2p site that might be ?? td? kickass ?
desperately need to know lol
Shiver me timbers, Avast!
thank you man; saved me from losing my phone data backup
Hi,
I want transfer data from laptop hard drive to external hard drive.
But my problem is I have tried to os system so the previous Windows is deleted.
How can I transfer data now ?
I used EaseUS Partition Manager Pro to convert mbr to gpt on a Dell laptop with Win 8.1 installed. No need for reformat or reinstall. Pretty scary process as it required a couple of reboots in its own special OS. Then after conversion process completed, on restart, I had to make sure that on reboot, it was set for UEFI or boot manager and not legacy. Otherwise, bsod results. Google promo code for Partition Manager Pro discount. With discount, not as expensive as discounted Paragon. Unit has been shutdown and restarted several times. No data loss and Win 8.1 works just as before conversion. Verified gpt conversion in diskpart and disk management. One of the more painless and easy process for this kind of application.
Guuys please help me I am using windows 8. 1 and it crashed for skme reason after attempting all the options available in the internet I choose to reinstall windows in that process I accidentally deleted the c drive in which windows was installed previously and now I am getting this error. So how to convert mbr to gtp so that i can install windows and retrieve my data and i cannot afford data loss. Please help me guyz
Same here @disqus_X5iAZ6nmLp:disqus
pls tell me what can i do….
Guyz does installing xp also have converting from mbr to gtp requirements???
so i have a 465gb HDD and ive split tmen into two partions one 235gb which i has my data and windows 7 and thie other on is formatted 230gb so i tried to install windows 8.1 on the second part but it said it was MBR and you need GPT so how to i convert the second partion to GPT without losing the data in the first partion.
I used AOMEI partition assistant, and one of my partitions dissappeared. I had to reformat the disk from windows setup in order to use all of it again. Luckily after I reinstalled windows, I used “get data back” and managed to recover everything I lost during format. I have a 1TB HDD.
Hi,
I’m in big trouble and wanna know how can I have GPT disk for ever and even formatting/deleting it.
Urgently need your response ASAP please????
Damn, why you delete my comment and what’s your problem with me?!
Me too but how ?!
Someone above asked about gdisk drive names. I found a reference that says \.: is 1st drive(zero, not O) \.1: for 2nd etc. is what it will accept.
is your hdd a data disk or boot disk?
*TOTALLY* false statement:
> One of the main challenges that we face while converting MBR to GPT is
that conversion is possible
> from MBR to GPT, only if there are no
partitions or volumes present in the disk – which makes it
> impossible to
convert without data loss
Impossible????
3 years later? Any answer?
hi guys , intersted to know also if there is any way to convert OS partition with out data lose
Starting with the Windows 10 Creators Update (b1703) everything is very easy now. No need to mess around with several tools. Just use in an elevated command shell the following command:
mbr2gpt.exe /convert /allowFullOS
…and you are done. This works under a running Windows 10 environment. After shutting down you have to switch to UEFI mode, of course.
Thorsten
Yes. This is mentioned in the last line of the post and covered here: https://www.thewindowsclub.com/mbr2gpt-tool-windows-10 :)
AZ Wizard Shyam Sasindran • 3 years ago
Is it possible to use AMOEI Partition Assistant as follows?
Clone Boot Drive C, now D
Boot from D
Convert original Boot Drive C to GPT
Remove Boot Drive D
Boot from original Boot Drive C which should now be in GPT format.
I need more space on my boot C (2 Tb), which is MBR, and by converting to GPT I can move to a 4Tb boot
Janice Shyam Sasindran • 3 months ago
3 years later? Any answer?
The answer is YES, I am using AMOEI Partition Assistant Pro. When cloning or copy C: to drive D: You will have to run the windows 8 system maintenance/repair option. it intern will discover both OS’s and enable them to be closable. when you boot your system. Most likely you will get three choices as I see when I boot my system in windows 8.1… I inadvertently had damaged my restorer partition but fixed in also thru this method.
I can not assure success as I might not remember every step I have taken. as I had also utilized the command prompt other tools as administrator.
Back it all up. than convert the drive using diskpart as administrator at a command prompt. you can always recover anything over written by running the recovery tool in AMOEI Partition Assistant. Than boot system using the dvd or USB and run auto repair option. THIS USUALLY WORKS if you’ve only converted from MBR to GPT. Rarely have loss of data.
Thank you very much !
AOMEI free, no longer supports GPT/MBR conversions. (tried to use it on Oct 26, 2017)
Well you’re using pro which is paid so no thanks
> This method you have to backup all your data and delete all partitions and
> volumes. Then use the DISKPART command.
Huh? After I destroy all my partitions… how do I then “just run diskpart” from the
cmd line”?
This article if loaded with many such oddities.
hello
i have formatted my c drive nd its asking gpt file and i donot want to loose any data please help me with this problem
Win-10 Computer was shut down for 15 days and after 15 day vacation Computer would not boot. Blue screen of death with the message ” Win-10 has MBR partion table on EFI system. Windows can only be installed on GPT disk”. Tried all repair functions in advanced, but nothing works. I would like to keep all my data if possible. I have the Win-10 Disk to reinstall but Microsoft said they could not help me because they could not take remote control of my computer. Pleas help Thank you. Roger Kolbo
This a waste of time. The program wants me to pay $40 just to convert my running windows disk.
What a rip-off
The MBR2GPT Disk Conversion Tool is free!