Windows cannot be installed on this disk. The selected disk is of the GPT partition style. In other cases, users can also encounter the following message: Windows Setup. Windows cannot be installed on this disk. The selected disk has an MBR partition table. On EFI systems, Windows can only be installed on GPT. 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. The selected disk is not of the GPT partition style”, it’s because your PC is booted in UEFI mode, but your hard drive is not configured for UEFI mode. You’ve got a few options: Reboot the PC in legacy BIOS.

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This article describes how to successfully set up dynamic boot partition mirroring on GUID Partition Table (GPT) disks.

Original product version: Windows Server 2012 R2
Original KB number: 814070

Summary

Unlike Master Boot Record (MBR) mirrors in 32-bit Windows, there are more steps to successfully create and boot to mirrored boot volumes on GPT disks. This article also describes how to recover after a primary disk failure if the shadow disk did not already have an EFI partition established. The disk must have an EFI partition to boot.

You must have the built-in Diskpart.exe and Bootcfg.exe utilities to create bootable mirror volumes on GPT disks. You can do some of these steps with the Disk Management console, but others you can do only with the built-in Diskpart.exe utility.

For consistency and ease of use, this article uses the Diskpart.exe utility to perform the steps. For help with any Diskpart.exe commands, start Diskmgmt.msc, and then open the help topics on the Help menu.

The steps are performed with real examples. The steps show the expected results returned from each command. Disk 0 is the primary system and boot drive. Disk 1 is the shadow drive.

Prepare the shadow drive for mirroring

Before you set up boot volume mirroring, it is a good idea have another GPT disk in the computer that contains an Extensible Firmware Interface (EFI) partition. The EFI partition contains the system files used to boot the operating system. If the primary system drive (disk-0) fails, you can use the EFI partition on the shadow drive (disk-1) to boot. This step creates and prepares new EFI and Microsoft Reserved (MSR) partitions on the shadow drive. You can use only the Diskpart.exe utility to create the required EFI and MSR partitions. You cannot use the Disk Management console to create or mirror EFI or MSR partitions.

Before you start, make sure that you have another BASIC disk with all unallocated free space of equal or greater capacity than the primary disks system and boot partitions. If you already converted the spare drive to dynamic, revert it back to basic before you follow these steps.

At a command prompt, run the Diskpart.exe utility.
This starts the diskpart console. After it is initialized, DISKPART> is displayed. It waits for your input commands.
Select the disk that you want to be the shadow drive, and then convert the drive to GPT. In this example, disk 1 is used for the mirror (shadow) drive.
Note
- The disk that you select must not contain any data partitions and must be a raw basic disk with only unallocated space of equal or greater capacity than the primary system disk.
- The following are the commands that you type at the command prompt.
- DISKPART> Select disk 1
  Disk 1 is now the selected disk.
- DISKPART> Convert GPT
  Diskpart successfully converted the selected disk to GPT format.
- DISKPART> List partition
  Partition ### Type Size Offset
  Partition 1 Reserved 32 MB 17 KB
  Note
  If you show more than one partition at this point, you have either selected the wrong drive, or you did not start with a raw drive. Correct this before you continue, or data loss may occur.
Select partition 1 on disk 1, then delete it - you must use the override command to delete the Microsoft Reserved (MSR) partition. You will re-create a new MSR partition after you create the required EFI partition.
- DISKPART> Select partition 1
  Partition 1 is now the selected partition.
- DISKPART> Delete partition override
  Diskpart successfully deleted the selected partition.
Select disk-0, and then list the partitions on disk-0. With the output of the list command, create new EFI and MSR partitions on disk 1 that are the same sizes as those on disk 0.
- DISKPART> Select disk 0
  Disk 0 is now the selected disk.
- DISKPART> List partition
  Partition ### Type Size Offset
  Partition 1 System 204 MB 32 KB <---- EFI PARTITION
  Partition 2 Primary 4996 MB 204 MB
  Partition 3 Reserved 32 MB 9 GB <---- MSR PARTITION
- DISKPART> select disk 1
  Disk 1 is now the selected disk.
- DISKPART> create partition efi size=204
  Diskpart succeeded in creating the specified partition.
- DISKPART> create partition msr size=32
  Diskpart succeeded in creating the specified partition.
- DISKPART> list partition
  Partition ### Type Size Offset
  Partition 1 System 204 MB 17 KB <---- NEW EFI PARTITION ON SHADOW
  *Partition 2 Reserved 32 MB 204 MB <---- NEW MSR PARTITION ON SHADOW
Select the EFI partition on the shadow drive, and then assign a letter to the EFI partition so it can be formatted. In this example, the drive letter S is assigned to the shadow EFI partition. You can use any available drive letter for this step.
- DISKPART> Select disk 1
  Disk 1 is now the selected disk.
- DISKPART> Select partition 1
  Partition 1 is now the selected partition.
- DISKPART> Assign letter=S
  Diskpart successfully assigned the drive letter or mount point.
Open a new command prompt, and then use the format utility to format the EFI partition (S:) with the FAT file system. You must do this so that you can copy the system files from the primary EFI partition to this new EFI partition. Do not format with NTFS. The system cannot boot from an EFI partition unless it is formatted with the FAT file system.
- C:> format s: /fs:fat /q /y
  The type of the file system is RAW.
  The new file system is FAT.
  QuickFormatting 204M
  Initializing the File Allocation Table (FAT)...
  Format complete.
  213,680,128 bytes total disk space.
  213,680,128 bytes available on disk.
  4,096 bytes in each allocation unit.
  52,168 allocation units available on disk.
  16 bits in each FAT entry.
  Volume Serial Number is EA34-03C7
Press ALT+TAB to return to the diskpart command window. Select the EFI partition on the primary drive (disk-0), and then assign a drive letter to that EFI partition. In this example, the drive letter P is assigned to the primary EFI partition on disk-0. You can use any available drive letter for this step.
- DISKPART> Select disk 0
  Disk 0 is now the selected disk.
- DISKPART> Select partition 1
  Partition 1 is now the selected partition.
- DISKPART> Assign letter=P
  Diskpart successfully assigned the drive letter or mount point.
Press ALT+TAB again to return to the other command prompt. Use the xcopy command to copy the system files from the primary EFI partition (P:) to the Shadow EFI partition (S:). You must do this to make sure that the shadow drive can boot the system if disk-0 fails. Make sure that you use the correct drive letters if you used different letters for your EFI partitions.
- C:> xcopy p:*.* s: /s /h

Windows Setup Gpt Partition Style