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.
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.