Installing Windows 8 on a UEFI PC can require a few tweaks. In this post you will learn how to prepare your boot media and PC setup, so Windows will make use of the advantages of the BIOS successor Unified Extensible Firmware Interface (UEFI).

Microsoft wants to push the BIOS successor UEFI with Windows 8. The enhanced UEFI support in Windows 8 and the requirements for hardware vendors to receive the Windows 8 logo demonstrate this. Nevertheless, installing Windows 8 on a Windows 8 PC is not as easy as it should be.

UEFI PC architecture

UEFI PC architecture

Windows 8 still can be installed on a BIOS PC, and UEFI is not required. However, if you have just purchased new hardware, then you probably want to make use of all its capabilities. The main advantages of UEFI are the support of GPT drives, which allow you to use more than 2TB of space, Secure Boot, and a faster boot-up process.

Not only is Windows 8 compatible with BIOS, but UEFI also comes with a Compatibility Support Module (CSM) that enables new PCs to mimic a BIOS. By the way, this also applies to Windows 8 x86, which doesn’t run on UEFI systems; only the 64-bit version supports UEFI.

Compatibility Support Module (CSM)

Compatibility Support Module (CSM)

This welcome support of old hardware and software can sometimes cause the Windows 8 setup to install a x64 Windows in compatibility mode. On many PCs, the CSM is enabled by default. For instance, computers with an Asus P8H77 mainboard, which run the AMI firmware, belong in this category.

If the setup runs into problems during the Windows 8 installation, the BIOS emulation will automatically be enabled and the PC will be treated like a computer with old hardware. You can avoid this behavior by disabling CSM in the PC setup. If you only install Windows 8, then you probably won’t need it anyway. The only exception is that the graphics adapter doesn’t support the UEFI Graphics Output Protocol.

Installation from a USB stick

Installing the operating system from a USB stick is a popular alternative to burning the ISO file on a DVD. Of course, the USB drive must be bootable and contain all the Windows 8 setup files. Microsoft offers the free Windows 7 USB/DVD Download Tool for this purpose.

However, almost all memory sticks are configured as MBR drives so that you can’t use them as boot media. Windows can only be started from GPT drives in UEFI mode. Thus, you first have to delete all partitions and then convert the drive into a GPT drive with the diskpart command convert gpt:

list disk
select disk <disk number>
convert gpt

Note: The diskpart tool is only for experienced users. Be careful not to delete the wrong drive.

A problem of the Windows 7 USB/DVD Download Tool is that it always formats an existing partition with NTFS, but FAT32 is required for booting up in UEFI mode. Depending on the hardware and firmware configuration, a Windows 8 setup that booted from an NTFS partition might automatically start the BIOS mode or even not boot up at all if CSM is turned off.



Hence, a better option is to configure the USB stick as a GPT drive with FAT32. The WiNToBootic tool supports this; however, during my tests, the free utility sometimes crashed with a meaningless error message. A more reliable utility is the free Windows 7 USB tool alternative Rufus.

Installing from DVD

Installing Windows 8 from a DVD usually doesn’t cause so many problems. In most cases, the only thing you have to do is configure the boot-up sequence in the PC setup. If MBR partitions already exist on the hard drive, you have to delete those during the setup process. Converting existing partitions is not possible. The system won’t be able to boot up on an UEFI PC if you install Windows 8 on a drive with existing MBR partitions.

Windows 8 Setup - Partitions

Windows 8 Setup - Partitions

If Windows 8 only creates one system partition aside from the installation partition, then you can assume that Windows will be installed in BIOS mode. On UEFI PCs, Windows only boots from GPT drives on which it creates an additional EFI system partition. If you don’t see this partition, you have to cancel the setup and try to find the reason why the setup is in BIOS mode.

This post is a translation of the German article Windows 8 auf UEFI-PCs installieren.

  1. Ian 10 years ago

    Hey! Quick correction for this guy – UEFI can boot to MBR devices.

    If you pull up the specs here: , you can see on Page 55 [Real page 113] of the PDF that support for booting from MBR devices is required (and, in fact, actually works on machines in practice! Haha.)
    “If a platform includes the ability to boot from a disk device […] partition support for MBR, GPT, and El Torito must be implemented”

    The flash drive would still need to be FAT32, but yeah, MBR is totally ok 🙂

    You guys rock! Keep churning out awesome content 😀

  2. Author

    Ian, sorry I have to disappoint you … whatever the UEFI specs may say, Windows doesn’t want to boot from MBR on UEFI systems. If you don’t believe me, please see this Technet article:
    “When you deploy Windows® to an EFI-based or UEFI-based computer, you must format the hard disk drive or other persistent storage device that includes the Windows partition by using a GUID partition table (GPT) file system.”

  3. Ian 10 years ago

    This is true, the installation of Windows needs to be on a GPT disc, but when booting from removable media (such as to a PE/Setup environment) MBR works perfectly well.


  4. Keith 10 years ago

    ISO2Disc is another freeware that could be used to create a GPT bootable USB drive from an ISO image. It will format your USB drive as FAT32 as well. It’s worth a try!

  5. zoki 10 years ago

    fufus is the best for creating uefi usb bootable

  6. zoki 10 years ago

    rufus sorry

  7. Ettercap 8 years ago

    I know how old this is but Ian is right, a removable storage can be bootable as a mbr in uefi boot and works perfectly fine you must it is only required to be GPT if launching from a HDD

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