GPT Partitions

For EFI computers that boot from a GPT disk, the boot disk must contain at least the following partitions:

• EFI System Partition On EFI computers, the EFI System Partition (ESP) is about 100 megabytes (MB) and contains the Windows Boot Manager files. The ESP has the following partition globally unique identifier (GUID):
  DEFINE_GUID (PARTITION_SYSTEM_GUID, 0xC12A7328L, 0xF81F, 0x11D2, 0xBA,
0x4B, 0x00, 0xA0, 0xC9, 0x3E, 0xC9, 0x3B)
• Microsoft Reserved Partition The Microsoft Reserved Partition (MSR) reserves space on each disk drive for subsequent use by operating system software. On drives smaller than 16 gigabytes (GB), the MSR is 32 MB. On drives 16 GB or larger, the MSR is 128 MB. GPT disks do not allow hidden sectors. Software features that formerly used hidden sectors now allocate portions of the MSR for feature-specific partitions. For example, converting a basic disk to a dynamic disk causes the MSR on that disk to be reduced in size, and a newly created partition holds the dynamic disk database. The MSR has the following partition GUID:
  DEFINE_GUID (PARTITION_MSFT_RESERVED_GUID, 0xE3C9E316L, 0x0B5C, 0x4DB8,
0x81, 0x7D, 0xF9, 0x2D, 0xF0, 0x02, 0x15, 0xAE)
• Data partition This partition stores Windows 7 system files and user files. The data partition has the following partition GUID:
  DEFINE_GUID (PARTITION_BASIC_DATA_GUID, 0xEBD0A0A2L, 0xB9E5, 0x4433,
0x87, 0xC0, 0x68, 0xB6, 0xB7, 0x26, 0x99, 0xC7);

Additionally, dynamic disks can use two different GPT partitions:

• A data container partition corresponding to the MBR partition 0x42, with the following GUID:
  DEFINE_GUID (PARTITION_LDM_DATA_GUID, 0xAF9B60A0L, 0x1431, 0x4F62, 0xBC, 0x68, 0x33, 0x11, 0x71, 0x4A, 0x69, 0xAD);
• A partition to contain the dynamic configuration database with the following GUID:
  DEFINE_GUID(PARTITION_LDM_METADATA_GUID, 0x5808C8AAL, 0x7E8F,
0x42E0, 0x85, 0xD2, 0xE1, 0xE9, 0x04, 0x34, 0xCF, 0xB3);

Data disks (non-boot disks) must have an MSR and a data partition. Standard users will typically see only the data partitions; however, the other partitions will be visible to administrators using the Disk Management snap-in or the DiskPart tool.