How-To Geek

How to Check if a Disk Uses GPT or MBR, and Convert Between the Two

Modern versions of Windows–and other operating systems–can use either the older Master Boot Record (MBR) or newer GUID Partition Table (GPT) for their partition schemes. Here’s how to check which one a disk is using and convert between the two.

These are just different ways of storing the partition table on a drive. GPT is more modern, and is required for booting Windows systems in UEFI mode. MBR is required for booting older Windows systems in BIOS mode, although the 64-bit version of Windows 7 can also boot in UEFI mode.

How to Check Which Partition Table Your Disk Is Using

To check which partition table your disk is using, you have two options:  You can use Windows’ graphical Disk Management tool, or you can use the command line.

Option One: Use the Disk Management Tool

You can view this information in the DIsk Management tool incldued with Windows. To access it, right-click the Start menu or press Windows Key+X and select “Disk Management.” You can also press Windows Key+R to open the Run dialog, type “diskmgmt.msc” into the box, and press Enter.

Locate the disk you want to check in the Disk Management window. Right-click it and select “Properties.”

Click over to the “Volumes” tab. To the right of “Partition style,” you’ll see either “Master Boot Record (MBR)” or “GUID Partition Table (GPT),” depending on which the disk is using.

Option Two: Use the Diskpart Command

You can also check using the standard diskpart command in a Command Prompt window. First, launch a Command Prompt window as Administrator by right-clicking the Start button or pressing Windows Key+X and selecting “Command Prompt (Admin).” You can also locate the Command Prompt shortcut in the Start menu, right-click it, and select “Run as Administrator.”

Type the following two commands, pressing Enter after each one:

diskpart
list disk

You’ll see a table listing your connected disks. If a disk is GPT, it will have an asterisk (that’s a * character) under the “Gpt” column. If it’s an MBR disk, it will be blank under the Gpt column.

For example, in the screenshot below, Disk 0 and Disk 1 are both GPT disks, while Disk 2 is an MBR disk.

How to Convert Between MBR and GPT: Back Up and Wipe Your Disk

To convert a disk from MBR to GPT, or from GPT to MBR, you’ll have to wipe the contents of the disk first. Before continuing, back up all the data on the disk. The conversion processes below will wipe the disk of all its data and partition tables, and then you’ll convert it to the new type of partition scheme and set it up from scratch again.

Technically, this isn’t the only way to convert between disks. Some third-party partition management programs promise they can convert MBR to GPT and GPT to MBR without any data loss. However, these aren’t officially supported by Microsoft, and you’d want to back up your data before running such programs anyway in case you lose anything.

We recommend just backing up the drive, wiping the data, and moving any necessary data back over. It may take a little longer than using a conversion feature, but this is the officially supported way and you’re guaranteed you won’t run into any partition problems or data loss.

Option One: Use Disk Management

Remember, back up any data on the disk before continuing! This will wipe all data on the disk you choose to convert!

To convert a disk to a different partition scheme, locate the disk in Disk Management. Right-click any partitions on the drive and select “Delete Volume” or “Delete Partition” to remove them. Repeat this process for each partition on that disk.

When all the partitions are removed from the disk, you can right-click the disk in Disk Management and select “Convert to GPT Disk” or “Convert to MBR Disk.” This option will only be available once all partitions have been wiped.

After you do this, you can create one or more partitions on the disk from the Disk Management window. Just right-click inside the unallocated space and create one or more new partitions. You can then move the data you backed up back onto the new partitions, if you like.

Option Two: Use the Diskpart Command

You can also do this with the diskpart command from a Command Prompt window. This may be necessary in some cases, as the diskpart clean command will allow you to modify partitions and disks that appear locked and unmodifiable in the graphical Disk Management tool.

Remember, back up any data on the disk before continuing! This will wipe all data on the disk you choose to convert!

First, launch a Command Prompt window as Administrator. Type the following commands into the Command Prompt window, one after the other:

diskpart
list disk

You’ll see a list of the disks on your computer. Note the number of the disk you want to convert. You can identify the disks by their sizes.

Now, type the following commands one after the other, pressing Enter after each, and replacing “#” with the number of the disk you want to convert. The “clean” command will wipe the contents of the disk and its partition records, so be very careful you select the correct disk number!

select disk #
clean

Now, type one of the following commands to convert the disk’s partition system to either MBR or GPT, depending on which you want.

To convert the disk from MBR to GPT:

convert gpt

To convert the disk from GPT to MBR:

convert mbr

You’re now done, and you can use the Disk Management window to create partitions on the disk or even use other diskpart commands in the Command Prompt to create those partitions. You can move the data you backed up back over to the new partitions, if you like..


Again, there are ways to convert between MBR and GPT without wiping the disk–in theory, at least. But we can’t verify the reliability of those third-party tools in every situation, so you’re generally better off using the officially supported method that wipes the disk. It may take a bit longer, but it’s guaranteed to work properly.

Chris Hoffman is a technology writer and all-around computer geek. He's as at home using the Linux terminal as he is digging into the Windows registry. Connect with him on Google+.

  • Published 03/19/16

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