Convert MBR Disk to GPT Disk

How to Convert a MBR Disk to a GPT Disk​

   Information

A disk is a separate physical hard drive. This will show you how to convert a MBR (Master Boot Record) disk to a GPT (GUID - Globally Unique Identifer) disk in Windows Disk Manager or in a command prompt. By default Windows uses MBR disks.

While all Windows can boot from a MBR disk, you can only boot from a GPT disk if your motherboard has an enabled UEFI BIOS and you have an operating system (Windows 7 or Windows 8) that supports booting to GPT that is installed with UEFI.

You can still have a separate GPT disk as a data disk if your operating system (see below) supports reading a GPT disk, even if your system disk that Windows is installed on is still a MBR disk.

   Note

Differences Between MBR and GPT Disks:

• MBR disks are supported (readable) by all Windows operating systems.
  • GPT disks are only supported (readable) by Windows server 2003 SP1 +, XP 64-bit, Vista, Windows 7, Windows Server 2008, Windows 8, and above.
• MBR disks use the standard BIOS partition table.
  • GPT disks use UEFI.
• MBR disks supports up to 2TB per single partition.
  • GPT disks supports up to 256TB per single partition in Windows.
• MBR disks supports up to 4 Primary partitions or 3 Primary partitions and 1 Extended partition with up to 128 logical volumes in the extended partition.
  • GPT disks supports up to 128 Primary partitions.
• Removable disks are MBR disks by default.
  • Removable disks cannot be converted into a GPT disk.

   Warning

• You must be an administrator to do this in Windows.
• Before you convert a disk, close any programs that are running on or from that disk.
• Before you convert a disk, be sure to backup anything that you do not want to lose on that disk to a separate physical disk location first. Converting the disk requires that all partitions and volumes are deleted on the disk.
• If you disable the Disk Defragmenter service, then you will get the error below when you try to do anything in Disk Management. If you get this error, then make sure that the Disk Defragmenter service is set to only Manual.

EXAMPLE: GPT disk vs MBR disk in Disk Management

OPTION ONE

In Disk Management

1. Open the Control Panel (icons view), and click on the Administrative Tools icon, then close the Control Panel window.

2. Click on Computer Management in Administrative Tools, then close the Administrative Tools window.

3. If prompted by UAC, click on Yes.

4. In the left pane under Storage, click on Disk Management. (See screenshot below)

5. In the disk (ex: Disk 1) that you want to convert to a GPT disk, right click on each partition and volume on the disk and click on Delete Volume until the whole disk is unallocated space. (See screenshot above)

6. Right click on the disk (ex: Disk 1) that you want to convert to a GPT disk, and click on Convert to GPT Disk. (See screenshot below)

7. When finished shortly, you can confirm that the disk is a GPT disk if you right click on the disk and it has Convert to MPR Disk instead now. (See screenshot below)

8. You can now create partitions on the now GPT disk if you like.

9. When done, close Disk Management.

OPTION TWO

In a Command Prompt

1. Open an elevated command prompt, and go to step 3 below.

OR

2. Open a command prompt at boot, and go to step 3 below.

3. In the command prompt, type diskpart and press enter. (See screenshot above)

4. Type list disk and press enter.
NOTE: Make note of the disk number (ex: Disk 1) that you want to convert to a GPT disk.

5. Type select disk # and press enter.
NOTE: Substitute # with the actual disk number that you want to convert to a GPT disk. For example, select disk 1.

6. Do step 7 or 8 below for what you would like to do.

7. To Use the "Clean" Command to make Disk Unallocated
NOTE: This is the easiest method. It will wipe the disk clean all at once leaving it as unallocated space afterwards.
A) In the command prompt, type clean and press enter.

B) Go to step 9 below.
8. To Manually make Disk Unallocated
NOTE: This method has you manually delete each volume on the disk before converting the disk to GPT.
A) Type detail disk and press enter. If the disk does not have any volumes listed, then you can go to step 8E below.
NOTE: This will give you a list of all the volume numbers on the selected disk number that you will need to delete in steps 7 and 8 below.

B) Type select volume # and press enter.
NOTE: Substitute # with a volume number listed in step 8A. For example, select volume 3.

C) Type delete volume and press enter.

D) Repeat steps 8B and 8C for each volume # listed in step 8A until you have deleted all volume #'s.

E) When done, type select disk # and press enter.
NOTE: You would use the same one from step 5 above. For example, select disk 1.
9. Type convert gpt and press enter.

10. When done, type exit and press enter.

11. Close the command prompt.

12. You can now create partitions on the now GPT disk if you like for a data disk, or start installing the supported Windows if you like. (See information box at the top of the tutorial.).
NOTE: Restart the computer if you did step 2 instead.
That's it,
Shawn

Related Tutorials

---

• How to Convert a GPT Disk to a MBR Disk
• How to Convert a Basic Disk to a Dynamic Disk
• How to Convert a Dynamic Disk to a Basic Disk
• How to Convert a FAT or FAT32 Volume to NTFS in Windows 7
• How to Extend a Partition or Volume in Windows 7
• How to Create a New Partition or Volume in Windows 7
• How to Delete a Partition or Volume in Windows 7
• How to Shrink a Partition or Volume in Windows 7
• How to Clean or Clean All a Disk with the Diskpart Command
• How to Quick Format a HDD or USB Drive

 

[Dinesh]

i'd like to convert it as i want to make a new primary partition but since i use MBR, i already have the max numbers of partition in my HDD.

 

[Brink]

All finished with the tutorial Dinesh. Convert away.

 

[Dinesh]

nice work Shawn. thanks.

 

[Brink]

You're welcome Dinesh.

 

[user666]

Wrong. You say "you can only boot from a GPT disk if you have a operating system (see below) that supports GPT and your motherboard has a EFI BIOS and is enabled." What you SHOULD say is "you can only boot from a GPT disk if you have a operating system (see below) that supports BOOTING TO GPT and your motherboard has a EFI BIOS and is enabled." Windows 7 32-bit DOES NOT SUPPORT BOOTING TO GPT! It DOES support reading GPT. That's not the same thing.

 

[Brink]

Hello user666, and welcome to Seven Forums.

I think it's pretty much understood as posted, but I'll edit it to help make clearer.

 

[sticco]

USB Recovery

hi, i have a similar but different problem. my flash drive has been changed to a MBR and i cannot even access it. if i try to format it , windows says it cannot complete format. i have tried everything but nothing seems to work.

pls help, how can i recover my flash back. it doesnt even show the capacity or disk size.

help pls

 

[Brink]

Hello Sticco, and welcome to Seven Forums.

You might see if running the clean all command on the flash drive may help. That commmand will wipe the drive completely as "unallocated space". Afterwards, you would just need to create a new partition or volume on it.

Hope this helps,
Shawn

 

[arkhi]

Windows 7 does not support booting to GPT, but does only support reading GPT.

Shawn, I think you should update this since Windows can boot to GPT since Vista SP1

 

[Brink]

Thank you Jim. Updated.

 

[Winefly]

Hey, the tutorial looks great but before I get started I have a question(s):

I just recently created a new build with a 3TB hard drive, which was setup by default as an MBR disk. Its been years since I was a PC user, so Ive learned the hard way that 3TB drives need to be formatted as GPT! I have a UEFI MoBo, and Windows 7 64 bit so I know that a GPT 3TB drive is bootable. I also know that all data will be lost when converting MBR to GPT....so the big question I have is- How do I clone/copy/backup my current data somewhere, convert to GPT, and then reinstall the data onto my 3TB GPT drive?

Can data that was stored in a MBR partition be cloned, then copied onto a GPT drive? Is this even possible? Basically what I want to do is have my existing drive be converted and all data, including OS be restored. Possible, or not possible?

 

[Brink]

Hello Winefly, and welcome to Seven Forums.

Yes, you will be able to copy the data to any other GPT or MBR drive to back it up, then be able to copy it back when finished converting it to a GPT drive.

In addition, you could also break the 3TB drive into either 3 X 1TB MBR partitions, or one 2TB and 1TB MBR partitions instead of having one large 3TB GPT drive.

http://www.sevenforums.com/tutorials/2674-partition-volume-create-new.html



Hope this helps,
Shawn

 

[arkhi]

Can data that was stored in a MBR partition be cloned, then copied onto a GPT drive? Is this even possible? Basically what I want to do is have my existing drive be converted and all data, including OS be restored. Possible, or not possible?

This is the command I used in command prompt to backup my drive to move it to GPT:

robocopy [I]C:[/I] [I]D:[/I] /mir /zb /copyall /dcopy:t /sl /xd "System Volume Information" /xf hiberfil.sys pagefile.sys /xj /r:0 /w:0 /tee /log:robocopylog.txt

Replace C: (Source) and/or D: (Destination) with your appropriate drive letter or folder path. Note that /mir will MIRROR your harddrive with the path, so if there are files in the destination that is not from the source, it will delete it. Make sure you put an empty drive or folder as the destination.

Also, if you're copying a Windows Vista and up installation, your junctions won't be copied and you'll need to do a repair install once you boot up your new GPT drive.

 

[Winefly]

Also, if you're copying a Windows Vista and up installation, your junctions won't be copied and you'll need to do a repair install once you boot up your new GPT drive.

Thanks for the reply, Shawn and Arkhi.

Im a bit of a novice...what are my junctions? Do you mean a repair install of Windows 7?

Another question.. Does my destination drive used for the backup and reinstallation need to be the same size as the drive I am converting...or just large enough to hold the current data volume?

 

[Brink]

Winefly,

Does the 3TB HDD have Windows installed on it, or is it just a data drive?

 

[Winefly]

The 3TB drive is my only current drive, booting with Windows 7 Pro x64 and all other data on it. The build is only a few weeks old, so I am probably only using at most 200GB currently. I am considering purchasing an SSD to move the OS onto...but for now, my primary concern is reformatting to GPT to access the 1TB unavailable to me in MBR format.

 

[Brink]

Winefly,

Could you post a screenshot of your Disk Management (diskmgmt.msc) window showing all of your HDD's layout to help see what other options you may have that may be easier for you to do?

You may be able to also break the 3TB MBR drive into either 3 X 1TB MBR partitions, or one 2TB and 1TB MBR partitions.

Partition or Volume - Create New

 

[Winefly]

Here it is, thanks!

 

[Brink]

Winefly,

If you just wanted to be able to use all of your 3 TB (2794.52 GB actually) HDD, then you do not have to convert it to be a GPT disk if you did not want to.

If you like so that you would not have to reinstall everything, you could start at step 2 in the tutorial below to only have to right click on the 746.52 GB Unallocated space in Disk Management and create a new partition with it to be able to use it all instead.

http://www.sevenforums.com/tutorials/2674-partition-volume-create-new.html