Windows 7: Convert MBR Disk to GPT Disk

Thank you Jim. Updated.

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?

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.

Partition or Volume - Create New



Hope this helps,
Shawn

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

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.

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?

Winefly,

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

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.

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

Here it is, thanks!

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.

Partition or Volume - Create New