Guide : How to convert your HDD from MBR to GPT if you only have a single HDD.(64bit)

Lyt

Lyt

New member
Hey guys, christmas is around the corner and I'm assuming many people are going to buy/get new hardware for their pc's. One of the problems you might run into with new motherboards is the new UEFI service over the original BIOS, that requires a GPT disk (HDD) to install a 64 bit OS ( I'm assuming the majority here use 64 bit systems) .

So here is a basic guide on how to convert a MBR (http://wiki.osdev.org/MBR_(x86)) disk to a GPT (https://wiki.archlinux.org/index.php/GUID_Partition_Table#Convert_from_MBR_to_GPT) disk if you only have one HDD.

Note : you cannot boot from GPT disk if you have BIOS and not UEFI, GPT is native to UEFI . x86 ( 32 bit ) systems with Vista+ OS can use GPT disks, but not boot off them.

What are the advantages of a GPT over MBR?
-MBR can only have 2.2 TB of space, GPT almost unlimited.
-Ability to make a lot more partitions.

As I said earlier , this only applies if you want to install a 64 bit OS.

So lets start. The conversion requires you to format the HDD. Backup everything you need.

-Once you have done that, insert your OS disk into the CD drive and restart windows.
-At the UEFI screen, press F11 and choose to boot from disk.
-It will take you to the windows install screen , where in the bottom left corner you must click on "Repair Windows" or something of that sort.
-Proceed to windows recovery, where you will be presented with a few options. Choose command console .
-In the cmd, type "diskpart" (without inverted commas), press enter. It will activate diskpart.
-Type "list disk" , press enter ,a list of your available disks will be displayed.
-Type "select disk <disknumber> " , press enter.
-Type "clean" to format the disk, press enter.
-Type "convert gpt" , press enter.
-Type "exit", press enter .

Now you will be able to install a 64 bit OS on the converted GPT disk .

Note : To boot from a USB stick, you have to enable Legacy boot in UEFI.

There are 3rd party programs you can use to convert a MBR disk to GPT without losing your data, but you have to pay. Haven't found a free one yet.

PS : I made this guide to save some possible hassle some of you might have. My internet was down at the time I encountered the problem, so had to figure it out for myself.

Thanks for reading.
 
Last edited:
Ooohhh crap, didnt see the section! I guess the mods will have to move it if they ever get around this section. Edited
 
One thing worth noting like Havoc said above. Windows can't boot off GPT partitions, so if you try to install Windows on a GPT partition, it'll format it back to MBR. My friend found this out the hard way when he bought a single 3TB drive where MBR can't see all 3TB but he can't use Windows if it's GPT.
 
S1ght said:
One thing worth noting like Havoc said above. Windows can't boot off GPT partitions, so if you try to install Windows on a GPT partition, it'll format it back to MBR. My friend found this out the hard way when he bought a single 3TB drive where MBR can't see all 3TB but he can't use Windows if it's GPT.
Click to expand...

Hey I don't think you can have one partition of the same disk use MBR and the other GPT. Its either one or the other, unless you have separate disks.

HavocXphere said:
Nice guide.

MS FAQ here >>> http://msdn.microsoft.com/en-us/library/windows/hardware/gg463525.aspx

And you should perhaps add a note that x86 systems (Vista+) can use GPT data disks...just not boot off them.
Click to expand...

Thanks, edited
 
Lyt said:
Hey I don't think you can have one partition of the same disk use MBR and the other GPT. Its either one or the other, unless you have separate disks.
Click to expand...

Maybe some bad explanation on my post but didn't mean to imply he used both on 1 drive.

I think the main point is if you're only planning to have 1 hard drive for your pc, don't bother with more than 2TB for now as you won't be able to use the rest.
 
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