Master Boot Record (MBR) disks use the standard BIOS partition table. GUID Partition Table (GPT) disks use Unified Extensible Firmware Interface (UEFI). One advantage of GPT disks is that you can have more than four partitions on each disk. GPT is also required for disks larger than two terabytes (TB).

Applies To: Windows 10, Windows 8.1, Windows Server 2019, Windows Server 2016, Windows Server 2012 R2, Windows Server 2012

[!NOTE] Before you convert a disk, backup any data on it and close any programs that are accessing the disk.

Converting using a command line

  1. Back up or move the data on the basic MBR disk you want to convert into a GPT disk.

  2. Open an elevated command prompt by right-clicking Command Prompt and then choosing Run as Administrator.

  3. Type diskpart. If the disk does not contain any partitions or volumes, skip to step 6.

  1. At the DISKPART prompt, type list disk. Note the disk number you want to convert.
list disk
  1. At the DISKPART prompt, type select disk <disknumber>.
select disk <disk n>
  1. At the DISKPART prompt, type clean.

    Running the clean command will delete all partitions or volumes on the disk.

  1. At the DISKPART prompt, type convert gpt.
convert gpt
  1. Type exit to quit cmd.