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How can I convert an MBR Hard Drive to GPT?

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December 4, 2013 12:01:16 PM

I am currently running Windows 7 Ultimate 32-bit and recently bought Windows 7 Home Premium 64-bit. I was going to perform a clean install of 64bit Home Premium but when selecting a drive to install it on, it told me that the OS couldn't install on an MBR drive and must be it GPT

I've tried converting my hard drive to GPT through:

Control Panel (icons) > Administrative Tools > Computer Management > Storage > Disk Management

Although when I right-Clicked on my drive, "Convert to GPT" was greyed out. I'm not concerned about data loss as this ia a new, relatively empty, but I'm worried about rendering my Hard Drive unusable if I use a program like Partition Wizard to force the conversion to GPT. Is there any way I can safely convert my MBR Hard Drive to GPT?

Is it because I have only one Hard Drive?

Specs:
CPU: Intel Core i7 4930K Hexa-Core 3.4GHz
Mobo: MIS X79A-GD45 (MS-7735)
Memory: Corsair 8GB DDR3 (2 x 4GB)
GPU: NVidia GeForce GTX760
Hard Drive: 1TB (single Hard Drive)

Is my motherboard able to support GPT? Do I need another Hard Drive?

Thanks in advance!
a b $ Windows 7
a c 311 G Storage
December 4, 2013 12:10:32 PM

yes, if the OS is running from a given hard drive it will not let you re-initialize the hard drive! The conversion will wipe everything on the drive.

If you are really willing to wipe everything on that drive and start over, you can use one of the bootable tools. You will probably have to go in stages. First delete all the partitions, then re-initialize the empty drive.

It seems to me that a UEFI motherboard will support a GPT drive. But the idea that Win7 refuses to install on a MBR drive is a complete and utter and total and shocking surprise to me.
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December 4, 2013 12:19:52 PM

How exactly do I go about deleting the partitions?
Say I do re-initialize my one and only drive so it's completely blank and a GPT drive. Will I be able to boot the Windows Home Premium 64-bit OS on there and install from there as if it were a completely new PC?
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a b $ Windows 7
a c 311 G Storage
December 4, 2013 12:28:34 PM

I'll answer the last question first - I've never heard of needing a GPT drive to install Win7 64-bit. I ran Win7 Pro 64-bit from an MBR drive for year.

Middle question: yes, you do initialize your one and only drive before doing the installation. You have the installation DVDs, yes?

First question: Download tool of choice and burn to bootable CD. The one I have closest to hand at the moment is PartedMagic: https://partedmagic.com/ . Boot the CD, open whatever the partition tool is called, and you will see a nice picture of your drive. Delete everything on it. Depending on which tool you are using, either select the drive and use the Initialize option on the menu or right-click on it and select Initialize from the dropdown menu. No harm in poking about if you don't care that the disk is being wiped - you can't permanently break the disk with these tools unless you do it deliberately.
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December 4, 2013 12:41:31 PM

WyomingKnott said:
I'll answer the last question first - I've never heard of needing a GPT drive to install Win7 64-bit. I ran Win7 Pro 64-bit from an MBR drive for year.

Middle question: yes, you do initialize your one and only drive before doing the installation. You have the installation DVDs, yes?

First question: Download tool of choice and burn to bootable CD. The one I have closest to hand at the moment is PartedMagic: https://partedmagic.com/ . Boot the CD, open whatever the partition tool is called, and you will see a nice picture of your drive. Delete everything on it. Depending on which tool you are using, either select the drive and use the Initialize option on the menu or right-click on it and select Initialize from the dropdown menu. No harm in poking about if you don't care that the disk is being wiped - you can't permanently break the disk with these tools unless you do it deliberately.


Yeah, I have the installation DVD, product key, all the necessary things. I thought it'd be as simple as installing any other OS, except I'd have to do a clean install (which I've done with ease before) because of the 32 bit to 64 bit jump, but Windows just kept telling me that Windows couldn't be installed because the drive I was installing on was MBR and it needed to be GPT, I had no idea what either of these were before today.

But thanks for your help, I'll burn the program to a disk, boot it up from startup, have a fiddle around to try and convert my drive to GPT. I'll post back here when I can with the results!
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a b $ Windows 7
a c 311 G Storage
December 5, 2013 6:00:17 AM

If possible, can you post a screenshot, or at least full text, of the error message and tell us which step in the installation process gives you that message? I'm having trouble understanding why it would come out.

Unless it's specific to the motherboard?
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a c 255 $ Windows 7
a c 98 G Storage
December 5, 2013 6:10:01 AM

At what point in the installation process are you getting the "GPT required" error message? There is absolutely no normal requirement that GPT be used to install Win 7, so there must be a configuration issue elsewhere in the process.

Are you actually booting from the Win 7 HP 64-bit DVD to start the installation process and then getting the error when you try to select the drive/partition to install to? Also, did you delete the previous partition during the same process?

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December 5, 2013 6:36:04 AM

Newer UEFI have a secure boot option (advanced UEFI) in the bios. This is for Windows 8 which can only install on GPT... I would rummage in the bios enabling "legacy boot" option which allows Windows 7 install to MBR.

Next would be booting into Windows 7 install and delete all partitions and re-initialize the drive.

These are my options (with a vague description on the right).

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December 5, 2013 7:13:04 AM

SebMarsh said:
How exactly do I go about deleting the partitions?
Say I do re-initialize my one and only drive so it's completely blank and a GPT drive. Will I be able to boot the Windows Home Premium 64-bit OS on there and install from there as if it were a completely new PC?


During full install you have the option to pick a partition to install to... highlight each one and select delete. (required or you wont be able to install).
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December 5, 2013 8:10:00 AM

WyomingKnott said:
If possible, can you post a screenshot, or at least full text, of the error message and tell us which step in the installation process gives you that message? I'm having trouble understanding why it would come out.

Unless it's specific to the motherboard?


COLGeek said:
At what point in the installation process are you getting the "GPT required" error message? There is absolutely no normal requirement that GPT be used to install Win 7, so there must be a configuration issue elsewhere in the process.

Are you actually booting from the Win 7 HP 64-bit DVD to start the installation process and then getting the error when you try to select the drive/partition to install to? Also, did you delete the previous partition during the same process?



The error appears when I'm selecting a partition to install Windows on and says:

"Windows cannot be installed to this disk. The selected disk has an MBR partition table. On EFI systems, Windows can only be installed to GTP disks."

I have two partitions, one for System Reserve, the other is the rest of my 1TB Hard Disk. I can't create any new partitions from this as the parition is not "Unallocated". The disk is also in NTSF system if that helps. I'm holding back on converting the disk to GPT as everyone so far has said that it's not a requirement for Windows 7, I'm going to look through my motherboard settings.

Here's a screenshot of my disk management window if that helps.

The CD-ROM is my Windows 7 64-bit DVD.

The error happens at this stage after clicking Custom Installation and clicking "More details" when the warning appears at the bottom. This isn't specific to my system, this is just an image of the step.

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a c 255 $ Windows 7
a c 98 G Storage
December 5, 2013 8:51:01 AM

Disk 1 Partition 1 is too small to use anyway. I recommend clicking on the Drive options (advanced link) and deleting both existing partitions and then letting Windows install via default settings.
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a b $ Windows 7
a c 311 G Storage
December 5, 2013 8:57:32 AM

Plus we have the answer right there. The board uses UEFI instead of BIOS, and requires a GPT partition. Probably for security reasons. It's your motherboard that's causing the message.

How big are disks 0 and 1, the whole drives? If that's your whole disk 1 it's kinda small.

Also: I strongly suggest removing the other hard drive from the system when you do the installation. If there is another drive when you install, and it is bootable, your boot data will remain on that drive and you won't be able to boot the new system drive without it.

The pics helped.
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December 5, 2013 9:28:22 AM



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December 5, 2013 9:34:00 AM

WyomingKnott said:
Plus we have the answer right there. The board uses UEFI instead of BIOS, and requires a GPT partition. Probably for security reasons. It's your motherboard that's causing the message.

How big are disks 0 and 1, the whole drives? If that's your whole disk 1 it's kinda small.

Also: I strongly suggest removing the other hard drive from the system when you do the installation. If there is another drive when you install, and it is bootable, your boot data will remain on that drive and you won't be able to boot the new system drive without it.

The pics helped.


The second image was not my system, it was just an image of the step itself. I have 1 Hard disk (disk 0 as shown in the first pic) that is exactly 931GB. I deleted the main partition which wiped the drive and kept the System Reserve (100MB), assuming it was important. But even with the disk space being totally unallocated, it still tells me it needs to be a GPT disk.

If it's because my board uses UEFI as opposed to BIOS, is there any way to make it boot up with BIOS or should I go ahead with trying to convert the disk to GPT? Also, is the System Reserve (100MB) partition safe to delete or should I leave it as is?

There are no other physical hard disks in the system, just the one.
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Best solution

a b $ Windows 7
a c 311 G Storage
December 5, 2013 11:18:11 AM

The system reserved partition is a part of your previous OS install, or of a failed install. Clobber it with a (figurative) brick. The drive must be empty of partitions to reinitialize as GPT.
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December 5, 2013 2:29:51 PM

WyomingKnott said:
The system reserved partition is a part of your previous OS install, or of a failed install. Clobber it with a (figurative) brick. The drive must be empty of partitions to reinitialize as GPT.


Exactly!

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December 6, 2013 9:54:33 AM

WyomingKnott said:
The system reserved partition is a part of your previous OS install, or of a failed install. Clobber it with a (figurative) brick. The drive must be empty of partitions to reinitialize as GPT.


Thank you everyone for your help! I booted up Partition Wizard with a bootable disc and deleted all the partitions so that the entire disk was unallocated. After that didn't work, I simply used Partition Wizard again to convert the unallocated disk to GPT and the OS installed.

Thanks again for all your help!
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a b $ Windows 7
a c 311 G Storage
December 6, 2013 11:21:21 AM

Glad it worked.
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