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

 

[ral77]

Oh... also.... reading through the tutorial, I also noticed that the "Option Two" section of the tutorial (the command line method) goes from step 8 to step 11. I'm *hoping* that no steps are actually missing, ie., I'm hoping that the numbering just got a little out of kilter but all the steps needed for command line formatting are actually there. Could someone tell me whether all the steps are indeed there or if somehow something got left out??

Gracias....

 

[Brink]

Hello Ral,

Thank you. Yeah, it was one of those late nights where the step numbers blurred together. All fixed now.

You're correct. A removable drive would be something like a USB flash drive instead.

 

[ral77]

Brink/Shawn:

Phew! Thanks for the info, I'm definitely glad to hear that I can format the external drive as GPT.

Regarding the "missing" (NOT!) steps of the tutorial -- interesting that no one else caught that. Just goes as evidence that us noobs actually *are* useful for something, and not always just a pain in the butt, lol...

 

[Brink]

I try to tailor my tutorials where even noobs can follow them without any problems, so any feedback to make them easier to follow or to point out mistakes is always welcomed.

 

[goodtime212]

how?

How do you do all this on brand new drives with no OS. I'm pulling my hair our now as I'm on my 2nd motherboard thinking the 1st one was faulty. Presently I have an Asus Z87-K and the one back in the box is a H87.
One drive is a Crucial 240g SSD + 2 x 1T sata drives

 

[Brink]

Hello goodtime212, and welcome to Seven Forums.

If you plan on installing Windows to the drive, then you do not want to convert it to GPT.

 

[goodtime212]

gpt

I've tried and tried over to install Win7 Ultimate. It goes through to the part where you choose the drive to install windows. It gets to the 'create partition' which it does and creates a system reserved + the partition and it won't format. I get error 0.80070057. The drive is not recognised in the bios boot list at the bottom but is listed on the sata list. I get the choice of ahci or ide I've tried both ways and get the same result.

 

[Brink]

You would want to have your BIOS set to AHCI since these are SATA drives.

The 0x80070057 error during installation means that the system reserved partition is corrupted.

https://support.microsoft.com/kb/2476568?wa=wsignin1.0

If there's nothing on the drive you want to keep, then you could also run a "clean" command ("clean all" would take to long) on the drive using the steps below to fix this error. It will be more thorough than the method above.

http://www.sevenforums.com/tutorials/52129-disk-clean-clean-all-diskpart-command.html

Afterwards, run the installation at boot to see if you are able to select it to install Windows on.

http://www.sevenforums.com/tutorials/1649-clean-install-windows-7-a.html

 

[goodtime212]

Thanks but I've tried that. I think I need the 'EFI' folder in the Windows install disk hasn't got newer files I there. No drivers for the HDD's. Windows 7 in the EUFI mode need 350m as the system partition and this version only gives 100m + 'too old' files'. Any thoughts?

 

[Brink]

Are you able to install Windows 7 without using UEFI?

 

[goodtime212]

No I'm afraid I haven't. The best I got was to the error number. I had a 3 week chat (EMails) with Asus and they say it's a faulty board but the guy I was 'talking to' wasn't the brightesty pebble on the beach..
I've had exactly the same with 2 Asus boards;
H87-Plus
K87N-H
I'm positive about this EFI folder in the install disk but don't knoq how to update it.
Thanks,
Ray

 

[Brink]

You might see if disabling UEIF in your BIOS settings, and then see if you may be able to boot from the installation media to install Windows 7 without UEFI.

If your motherboard has secure boot, be sure to disable it as well.

 

[goodtime212]

It gives the option of ahci/ide in the bios. I can't find secure boot. I tried it with ide chosen and booted from the win7 and not from the eufi win7 and got exactly the same thing 0.80070052 at format. The guy from Asus was absolutely clueless with it all and told me to go to my supplier for a replacement. I used to work in ITC, Networking and telecoms... 15yrs. Retired now but determined to beat this.
I have another PC with a eufi bios that works fine. I'm going to try putting win7 on that and then put it in the Asus. It's the Intel 81 chipset but, hopefully, it will just need the drivers fixing to the 87 set.
cheers,
Ray

 

[Brink]

Yeah, you'll need to use AHCI.

Just to verify, were you able to run the "Clean" command in a command prompt at boot on the hard drive to wipe it, then create a new primary partition?

http://www.sevenforums.com/tutorials/52129-disk-clean-clean-all-diskpart-command.html

 

[Kalhur]

Well I have 1 disk (disk 1) and it doesn't let me to convert it to GPT, do I have to set another disk ?

 

[Brink]

Hello Kalhur, and welcome to Seven Forums.

If this is your Windows disk, then you will not be able to convert it to GPT since it's in use by Windows.

You really would only need to convert a disk to GPT if you you planned on having partitions larger than 2 TB in size.

 

[dmms]

Thanks

Searched for hours and reviewed 20 sites that explained this procedure-- badly! (even support.ms). This tutorial is the ONLY one that contained clear instructions. I teach technical writing so I know whereof I speak-- good job (and, BTW, I finally got my MBR HD converted to GPT in order to install Win 7 64 bit).

 

[Brink]

Hello dmms, and welcome to Seven Forums. I'm glad this tutorial was able to help.

 

[jasonsmith]

When using an external hard drive for data storage. Does formatting it to GPT offer better protection from viruses or being more reliable than if it was set to MBR?

I believe in the boot part of the drive, GPT is more resistant to viruses infecting that section due to how it is designed than MBR. Also, not sure how well anti-virus scans the boot sector.

Also, it sounded like GPT could be more reliable in that the "boot" section has redundancy and self check compared to how MBR doesn't have that.

 

[Brink]

Hello Jason,

The quick answer is no for helping to prevent viruses. To help with protecting prestartup of Windows you would need to have Windows installed with UEFI and have Secure Boot enabled.

GPT is more resilient, but is often not used unless you have Windows installed with UEFI or the drive is larger than 2TB.