Step-by-Step Guide to Convert from MBR to GPT

Affected Operating Systems:

• Windows 10

Table Of Contents

• Why should I convert my hard drive to GPT?
• How to convert a disk from MBR to GPT format
  • Converting from MBR to GPT using Command Prompt
    • Converting to GPT format using Command Prompt in Windows Setup
  • Converting from MBR to GPT using Windows Disk Management
    • How to initialize a disk drive using GPT
  • Converting from MBR to GPT using MBR2GPT.exe
• Other resources

Why should I convert my hard drive to GPT?

GUID Partition Table (GPT) takes advantage of UEFI BIOS to support storage devices larger than 2TB and lets you set up as many partitions as you need (Microsoft Windows supports up to 128 partitions on a GPT drive). The Windows 10 operating systems can use the UEFI BIOS, which can speed up boot and shutdown times and provides additional security advantages. To boot your computer in UEFI mode, you must use a drive formatted using the GPT drive format.

Windows 10 operating systems on Dell computers that were downgraded to Microsoft Windows 7 at the factory were shipped with the hard drive set to Master Boot Record (MBR) format. If you are upgrading your computer to Windows 10, it is recommended you convert the hard drive to GPT format.

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How to convert a disk from MBR to GPT format

Converting from MBR to GPT using Command Prompt

Converting to GPT format using Command Prompt in Windows Setup

1. Power off the computer, and insert or connect the Windows installation DVD or USB drive.
2. Power on the computer and tap F12 key until the One-Time Boot Menu appears.
3. Select the Windows installation DVD or USB in the menu and press Enter key.
4. From the Windows Setup screen, press Shift + F10 key to open a Command Prompt window.
5. In the Command Prompt window, type diskpart and press Enter key.
6. To identify the disk drive to reformat, type list disk and press Enter key.
7. To select the drive and reformat it, type select disk # (substitute # with the disk number for example select disk 1) and press Enter key.
8. Type clean and press Enter key.
9. Type convert gpt and press Enter key.
10. Type exit and press Enter key.
11. Close the Command Prompt window. If you are installing Windows, go to the Windows Setup process.

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Converting from MBR to GPT using Windows Disk Management

How to initialize a disk drive using GPT

1. Click Start, type diskmgmt.msc in the Start search box.
2. Right-click diskmgmt.msc and click Run as Administrator.
   Note: When Windows detects a non-initialized disk, select the Disk, choose GPT, and click OK.
3. Verify that the disk status is Online, else right-click and select Initialize disk.
4. If the disk is already initialized, right-click the label on the left and click Convert to GPT Disk.
5. Once the disk has been initialized, right-click the unallocated space and click New Simple Volume and follow the steps to complete the process.

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Converting from MBR to GPT using MBR2GPT.exe

Reference the following Microsoft Documents for instruction. Convert MBR partition to GPT

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