Change a GUID partition table disk into a master boot record disk

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

To change a GUID partition table disk into a master boot record disk

Back up or move all volumes on the basic GUID partition table (GPT) disk you want to convert into a master boot record (MBR) disk. If the disk does not contain any partitions or volumes, skip to step 2.

For more information about backing up volumes, see Related Topics.
Open Computer Management (Local).
In the console tree, click Computer Management (Local), click Storage, and then click Disk Management.
If the disk does not contain any partitions or volumes, skip to step 5. Otherwise, right-click the any volumes on the disk and then click Delete Volume.
Right-click the GPT disk that you want to change into an MBR disk, and then click Convert to MBR disk.

Notes

To perform this procedure on a local computer, you must be a member of the Backup Operators group or Administrators group on the local computer, or you must have been delegated the appropriate authority. To perform this procedure remotely, you must be a member of the Backup Operators group or Administrators group on the remote computer. If the computer is joined to a domain, members of the Domain Admins group might be able to perform this procedure. As a security best practice, consider using Run as to perform this procedure. For more information, see Default local groups, Default groups, and Using Run as.
To open Computer Management, click Start, click Control Panel, double-click Administrative Tools, and then double-click Computer Management.
You can change a disk from GPT to MBR as long as the disk is empty.
Itanium-based computers, x86-based computers running Windows Server 2003 with Service Pack 1 (SP1), and x64-based computers support both MBR and GPT disks.

Back up or move all volumes on the basic GUID partition table (GPT) disk you want to convert into a master boot record (MBR) disk. If the disk does not contain any partitions or volumes, skip to step 2.

For more information about backing up volumes, see Related Topics.
Open Command Prompt.
Type:

diskpart

If the disk does not contain any partitions or volumes, skip to step 7.
At the DISKPART prompt, type:

list volume

Make note of the number of the volume that you want to delete.
At the DISKPART prompt, type:

select volume n
At the DISKPART prompt, type:

delete volume
At the DISKPART prompt, type:

list disk

Make note of the disk number of the disk that you want to convert to an MBR disk.
At the DISKPART prompt, type:

select disk n
At the DISKPART prompt, type:

convert mbr

Important

The disk must be empty to convert it to an MBR disk. Back up your data and then delete all partitions or volumes before converting the disk.

Value	Description
list volume	Displays a list of basic and dynamic volumes on all disks.
select volume	Selects the specified volume, where n is the volume number, and gives it focus. If no volume is specified, the select command lists the current volume with focus. You can specify the volume by number, drive letter, or mount point path. On a basic disk, selecting a volume also gives the corresponding partition focus.
delete volume	Deletes the selected volume. You cannot delete the system volume, boot volume, or any volume that contains the active paging file or crash dump (memory dump).
list disk	Displays a list of disks and information about them, such as their size, amount of available free space, whether the disk is a basic or dynamic disk, and whether the disk uses the master boot record (MBR) or GUID partition table (GPT) partition style. The disk marked with an asterisk (*) has focus.
select disk	Selects the specified disk, where n is the disk number, and gives it focus.
convert mbr	Converts an empty basic disk with the GUID Partition Table (GPT) partition style to a basic disk with the master boot record (MBR) partition style.

Notes

To perform this procedure on a local computer, you must be a member of the Backup Operators group, Administrators group, or you must have been delegated the appropriate authority. If the computer is joined to a domain, members of the Domain Admins group might be able to perform this procedure. As a security best practice, consider using Run as to perform this procedure. For more information, see Default local groups, Default groups, and Using Run as.
To open a command prompt, click Start, point to All programs, point to Accessories, and then click Command prompt.
You can change a disk from GPT to MBR as long as the disk is empty.
Itanium-based computers, x86-based computers running Windows Server 2003 with Service Pack 1 (SP 1), and x64-based computers support both MBR and GPT disks.
For more information about DiskPart, see Related Topics.

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