Convert GPT hard drive to MBR

Depending on the version of the operating system previously installed, it may be difficult or even impossible to install a new version of Windows on top, despite formatting the partitions. This mainly concerns the installation of Windows (XP, Vista, 7, 8, 8.1 or 10) on a UEFI Bios.

Example: Windows 8 or Ubuntu was installed on the PC but you wish to put Windows 7. On the disk selection screen, the partitions are invalid or the installation does not come to an end. This can happen when a partition is configured in GPT.

The operation is easier to perform when it is a secondary disk that can be plugged into a computer (internal SATA or USB), but if it is the main hard disk of the tower or laptop, the thing is more complicated to do. This tutorial explains in a simple way how to do it.

This guide also works to format a hard drive without having an operating system on your computer. What to sell or give away a PC without anything on it.

Convert GPT disk to MBR from Windows installation

1. Load Windows installation media, DVD or USB key. No matter the version of Windows: 7, 8, 10.

2. Start on this medium to start the Windows installation process.

3. Go through the first steps until you get to the question of the type of installation you want: choose the second option ” Custom (advanced option) ” Where ” Custom: install Windows only » depending on the OS already installed on the disk.

Windows 10 install tutorial

4. The list of partitions is displayed. If more than one disk is connected, be careful not to delete the wrong hard disk (identified by Disk 0, Disk 1, etc).

Windows diskpart hard drive tutorial

5. Press SHIFT + F10 (Shift + F10). The Shift key is the up arrow key, not the padlock. This opens a Command Prompt, characterized by its black screen.

Windows diskpart hard drive tutorial

6. Type “ diskpart to launch the Windows Diskpart utility.

Windows diskpart hard drive tutorial

7. Write “ list disk to display the hard drives connected to the PC. In this example, a single 20GB disk.

Windows diskpart hard drive tutorial

8. Type “ select disk 0 (or other disk number) to work on the correct hard drive. By default, the main disk of the machine is 0.

Windows diskpart hard drive tutorial

9. Enter ” clean to erase all partitions on this disk.

Windows diskpart hard drive tutorial

10. Write “ convert mbr to convert the disc to MBR format. The operation is immediate.

Windows diskpart hard drive tutorial

11. Exit Diskpart by typing ” exit » and close the Command Prompt by retyping « exit » .

Windows diskpart hard drive tutorial

12. Returning to the disk selection screen to install Windows, click on the button Refresh. Only one blank partition appears for the disk diskpart worked on: Unallocated space on disk 0

Windows diskpart hard drive tutorial

13. The hard disk is now empty of any partitions. You can install an operating system on it, sell it, turn it into a storage or backup disk, etc.