Master Boot Record (MBR) disks use the standard BIOS partition table. GUID Partition Table (GPT) disks use Unified Extensible Firmware Interface (UEFI). MBR disks do not support more than four partitions on each disk. The MBR partition method is not recommended for disks larger than two terabytes (TB).

You can change a disk from a GPT to an MBR partition style as long as the disk is empty and contains no volumes.

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

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 all volumes on the basic GPT disk you want to convert into an MBR 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 mbr.
convert mbr
  1. Type exit to quit cmd.