Cant install Windows 10 because of GPT partition error message

The UEFI firmware supports two boot modes: UEFI mode and Legacy BIOS mode.

- UEFI mode uses the GUID Partition Table (GPT) partition style.
- Legacy BIOS mode uses the Master Boot Record (MBR) partition style.

On many computers, you can boot from the Windows 10 USB/DVD installation media either in UEFI mode or in Legacy BIOS mode.

Here is an example of the one-time boot menu.



You receive an error message when you try to install Windows 10

If you receive the error message: "Windows cannot be installed to this disk. The selected disk is of the GPT partition style", it’s because your computer is booted in Legacy BIOS mode, but your hard drive is not configured for Legacy BIOS mode.

You have two options when you get that error message.

Option 1: Boot from the Windows 10 USB/DVD installation media in UEFI mode, so you can use the GPT partition style. This option lets you keep the existing partition style and lets you use the PC’s UEFI firmware features.

Option 2: Delete all partitions on the hard drive, so you can use the MBR partition style. In other words, you convert GPT disk to MBR disk. This option is not recommended because then you will not be able to use the PC’s UEFI firmware features.



If you receive the error message: "Windows cannot be installed to this disk. The selected disk has an MBR partition table. On EFI systems, Windows can only be installed to GPT disks", it’s because your computer is booted in UEFI mode, but your hard drive is not configured for UEFI mode.

You have two options when you get that error message.

Option 1: Boot from the Windows 10 USB/DVD installation media in Legacy BIOS mode, so you can use the MBR partition style. This option lets you keep the existing partition style. This option is not recommended because then you will not be able to use the PC’s UEFI firmware features.

Option 2: Delete all partitions on the hard drive, so you can use the GPT partition style. In other words, you convert MBR disk to GPT disk. This option lets you use the PC’s UEFI firmware features.



Installing using the GPT or MBR partition style

If you want to use the GPT partition style, you must boot from the Windows 10 USB/DVD installation media in UEFI mode (marked UEFI in the boot menu). If you want to use the MBR partition style, you must boot from the Windows 10 USB/DVD installation media in Legacy BIOS mode (not marked UEFI in the boot menu).

You do not need to delete all partitions if you want to keep the existing partition style (GPT or MBR), but in that case you need to make sure that Windows Setup boots to the correct firmware mode (UEFI or Legacy BIOS).

The "convert gpt" and "convert mbr" commands are useless, if you want to change the partition style (GPT or MBR). Boot from the Windows 10 USB/DVD installation media either in UEFI mode or in Legacy BIOS mode. After that, on the "Where do you want to install Windows?" screen delete all partitions on the hard drive until it's unallocated. Installing to the unallocated space and letting Windows Setup create the partition style and partitions works with both UEFI mode and Legacy BIOS mode.

On a GPT disk, Windows Setup will create a Recovery partition, an EFI system partition, a Microsoft Reserved partition (won't show in Disk Management) and a primary Windows partition. On an MBR disk, Windows Setup will create a System Reserved partition and a primary Windows partition.

Source: Microsoft

Windows Setup: Installing using the GPT or MBR partition style

Many PCs now include the ability to use the UEFI version of BIOS, which can speed up boot and shutdown times and can provide additional security advantages. To boot your PC in UEFI mode, you'll need to use a drive formatted using the GPT drive format.

Many PCs are ready to use UEFI, but include a compatibility support module (CSM) that is set up to use the legacy version of BIOS. This version of BIOS was developed in the 1970s and provides compatibility to a variety of older equipment and network configurations, and requires a drive that uses the MBR drive format.

However, the basic MBR drive format does not support drives over 4TB. It's also difficult to set up more than four partitions. The GPT drive format lets you set up drives that are larger than 4 terabytes (TB), and lets you easily set up as many partitions as you need.

Boot to UEFI mode or Legacy BIOS mode

Boot into UEFI mode or legacy BIOS-compatibility mode when installing Windows from your USB, DVD, or network location.

If you install Windows using the wrong mode, you won’t be able to use the features of that firmware mode without reformatting the drive.

Select the firmware mode during bootup.

1. Boot the PC. As the firmware starts to run, press the key that opens the boot device menu. For example, press the Esc, F2, F8, F9, F12, or other key to enter the firmware or boot menus.

2. On the boot device menu, select the command that identifies both the firmware mode and the device. For example, select UEFI USB Drive or Network - BIOS.

   Note

You might see separate commands for the same device. For example, you might see UEFI USB Drive and BIOS USB Drive. Each command uses the same device and media, but boots the PC in a different firmware mode.

How to check that you are using either UEFI mode or Legacy BIOS mode

If the entire hard drive not show as unallocated space, then delete all partitions on the hard drive until it's unallocated. Select a partition and click on the "Delete" option for each partition.

After that, select the "New" and "Apply" buttons.









How to check that your Windows 10 USB flash drive works with UEFI mode

If your Windows 10 USB flash drive is formatted as FAT32 file system, then it should be bootable in UEFI mode.

When you boot from the USB flash drive, UEFI mode starts the boot process either from the "\efi\boot\bootx64.efi" file or from the "\efi\boot\bootia32.efi" file. There are only a few computer systems that have the 32-bit UEFI firmware and in that case you must use a 32-bit version of the Windows 10 USB flash drive.

How to create a bootable USB flash drive to install Windows 10

USB Flash Drive - Create to Install Windows 10

OPTION ONE: Use Media Creation Tool to create Bootable Windows 10 USB for Legacy BIOS and UEFI

Note: Media Creation Tool creates a USB flash drive that works with both UEFI mode and Legacy BIOS mode.

OPTION TWO: Use "Rufus" to create Bootable Window 10 USB for Legacy BIOS and UEFI

Note: Rufus is unable to create a USB flash drive that can be booted in both UEFI mode and Legacy BIOS mode.

How to create a bootable USB flash drive from the Windows 10 ISO image file, that works with both UEFI mode and Legacy BIOS mode

- Connect your USB flash drive.
- Open a command prompt as administrator and type (or copy and paste) the following commands.

diskpart
list disk (make note of the USB flash drive disk number)
select disk # (where # is the USB flash drive disk number)
clean
create partition primary
format quick fs=fat32
active
exit

- Right-click the Windows 10 ISO image file and choose "Mount". If you don’t see mount command from the context menu, go to "Open with" > "Windows Explorer" instead.
- Copy the files and folders from the mounted Windows 10 ISO image file to the USB flash drive.

How to create a bootable USB flash drive from the Windows 10 ISO image file, that only works with UEFI mode

UEFI mode do not require a partition to be set as active.

- Connect your USB flash drive.
- Format the USB flash drive to FAT32 file system (see screenshot below). The default "Allocation unit size" setting is automatically detected, so do not change the setting.
- Right-click the Windows 10 ISO image file and choose "Mount". If you don’t see mount command from the context menu, go to "Open with" > "Windows Explorer" instead.
- Copy the files and folders from the mounted Windows 10 ISO image file to the USB flash drive.



Windows support for large-capacity disks as non-booting data volumes

Look at post #5 in this thread: I want to convert drive 4 to gpt

How to fix the Windows 10 bootloader

Look at post #24 in this thread: How do I restore w10 bootloader? dual boot with ubuntu on separate hdd