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

 

[Brink]

Interesting.

 

[ICIT2LOL]

Hello Shawn I was trying to get this new 750GB drive ready for use as a clone to and have ended up with a drive that is just not going to do anything.

have I wrecked it somehow as other programs report it as read only - am really confused as I have never come across this before.

 

[beardrinksbeer]

I take it you have formatted it. did you go into device manager and see if it was there? sometimes it won't do anything to the drive until it loads the driver for it. what programs have you tried? have you tried "clean" or "clean all" in diskpart? what is your OS? are you trying to format it ready for cloning in MBR; GPT is for HDD over 2TB. what cloning program are you using? did you use the cloning program to see if it "sees" the HDD

sorry to jump in Brink

 

[ICIT2LOL]

Well I tried using the diskpart to format it and create a primary partition etc etc in my partners 7 machine and then in my 8.1 and no change.

I even tried using Partition Wizard to do something with this drive but it just comes up nothing as I said the thing is there albeit something less than the 750Gb I bought and in 7 says read only so I ma completely lost as to what the darn thing is now.
What I really don't understand is the not initialised and unallocated as in my pic

 

[beardrinksbeer]

in disk management what does the HDD say when you right click it? does it show a dailogue to format the HDD? I can't remember what part you have to right click it thou, the left or right part of the diagram.

what sort of HDD is it? how old is the HDD?

does the HDD show up in device manager?

cheers

 

[jumanji]

Have you tried getting into that disk in diskpart and then
ATTRIBUTES DISK CLEAR READONLY
ATTRIBUTES VOLUME CLEAR READONLY

And what is the message you get when you try to initialise it?

You may also try this:

Open the disk properties and goto the Drivers tab
Uninstall the driver
Reboot your PC
When it starts up again, Log in and it should say that the device has been installed successfuly.
Reboot again (if windows doesnt tell you to)

http://answers.microsoft.com/en-us/...ead-only/d2642d40-cd65-4cc7-8146-627345dfe0e6

 

[ICIT2LOL]

bear the drive is brand new as I said first up and right clicking does nothing apart form the Properties and such and really nothing of anyhelp.

Hey jumanji I'll give that a burl as it is driving me nuts mate. First I'll give the drivers option a go.

 

[ICIT2LOL]

Ok Jumnaji mate I did the first option and updated the driver but it said that the best driver was already installed so it must have happened real quick. But in any case the partition if that what it is in now healthy and the Not initialised has gone.
What is still bothering me is that it was bought and it states on it 750GB and the admin window shows it is 698.83GB?? that is at least 50GB short of what the device says it is.

So anyway does this mean I have to format the drive again? Sorry mate but drive stuff like this is very convoluted for me.

 

[beardrinksbeer]

I was going to answer this but he seems to like u Jumnaji & not a fellow Aussie (even thou he can't write the native language), u can explain the 1024 & 1000 thingy

cheers

 

[jumanji]

I was going to answer this but he seems to like u Jumnaji & not a fellow Aussie (even thou he can't write the native language), u can explain the 1024 & 1000 thingy

cheers

I really can't understand your aboriginal language .( just pulling a fast one. )

Anyway I don't want to explain 1024 and 1000. ICit2 can find it out.

@ICit2, everything seems to be fine with the disk now.

To make you sleep well, here is a screenshot of my 750GB Seagate Goflex external drive (Disk 1).



Hope you sleep well. Good night.

( You may run Partition Recovery Wizard to check whether it can find whatever you have done.)

 

[ICIT2LOL]

Thanks Jumanji the driver fix worked out just right and I am now cloning the drive for the boss

Such a simple thing but to be honest as I said the stuff involving drives is overly convoluted for silly old fellows like me.

 

[ICIT2LOL]

I was going to answer this but he seems to like u Jumnaji & not a fellow Aussie (even thou he can't write the native language), u can explain the 1024 & 1000 thingy

cheers

Actually a naturalised Pom mate and yep I do understand the basic alignment and formatting stuff it is the other run arounds that that throws me
by the by what is the native language as I don't use the new stuff young fellas like "u" use

 

[Brink]

Ok Jumnaji mate I did the first option and updated the driver but it said that the best driver was already installed so it must have happened real quick. But in any case the partition if that what it is in now healthy and the Not initialised has gone.
What is still bothering me is that it was bought and it states on it 750GB and the admin window shows it is 698.83GB?? that is at least 50GB short of what the device says it is.

So anyway does this mean I have to format the drive again? Sorry mate but drive stuff like this is very convoluted for me.

Glad you got it sorted John.

Just out of curiosity, did you try right clicking on the smaller Disk 2 box you have circled in red in your Disk Management screenshot, and click on Initialize?

Here's more information on why your HDD is not be the size as advertised:

HDD's - the Advertized size vs the Actual size.

 

[ICIT2LOL]

Hello Shawn well I could do that mate because that option was greyed out or I would have done just that why it was so is a mystery. Anyway jumanji was right on the money with the answer with that uninstall driver option.

I am as I said to him and the others not good at understanding how to get hard drives ready for use and all that partitioning stuff as you can se my pic of the C: drive - I have no idea of how to put that right even though it makes no difference to how the SSD performs.

Thanks for the link mate I know that most drive sizes are not really what they are stated to be but I did think 50GB out was a little bit rude. Mind you I really am not a fan of WD preferring Seagate myself.
Having said that the clone is definitely quicker between programs on the taskbar and booting up.

 

[Brink]

Personally I like to start an installation with an unallocated drive to help avoid funky partitioning like that, then partition afterwards how I like.

 

[ICIT2LOL]

Shawn I shall have to do some researching on the matter as I thought being unallocated was or meant the drive was unusable as is

 

[Brink]

Shawn I shall have to do some researching on the matter as I thought being unallocated was or meant the drive was unusable as is

Unallocated is unusable, but you could select an unallocated drive say during Windows installation to have it automatically formatted and then used to install Windows on like in step 7 or 8 below.

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

 

[ICIT2LOL]

Got that Shawn but just out of curiosity is that 100MB space the same sort of aligning method as in Wolfgang's tutorial on SSD's? so to just make it neat and "tidy" so to speak?

 

[Brink]

I don't remember which tutorial is the one for Wolfgang that you mentioned.

The 100 MB partition is the System Reserved partition created during installation to be able to use WinRE without the need of a system repair disc or installation media.

 

[ral77]

Hello...

(VERY) infrequent poster, here, but I figured this might be the place to straighten me out about this. I recently bought a 2TB Western Digital MyBook hard drive. to use as an additional data drive for my laptop. Although since it's only 2TB (a bit less than that being usable, of course) I *could* just format it as an MBR drive, but I thought I'd like to format it as GPT, for a couple of not-absolutely-essential reasons.

When looking through this tutorial, I noticed that at the very start of it you've provided a little section contrasting the differences between MBR and GPT formatted drives. The very last thing mentioned is "Removable disks cannot be converted into a GPT disk."

Eeeeek!! Would my external USB-connected hard drive be considered a "removable drive"? I vaguely think I remember reading that "removable drive" as defined by Windows would mean a USB thumb drive, or optical media like a DVD drive, but would NOT apply to an external hard disk such as what I have. Could someone tell me (definitively) whether external USB hard drives can be formatted as GPT?

Thanks so much, in advance...