Partitions of Windows 10 or 11

UEFI/GPT-based hard drive partitions

The default partition layout for UEFI-based PCs is: a system partition, an MSR, a Windows partition, and a recovery tools partition.

efi partition layout

DISKPART> list partition

  Partition ###  Type              Size     Offset
  -------------  ----------------  -------  -------
  Partition 1    System             100 MB  1024 KB
  Partition 2    Reserved            16 MB   101 MB
  Partition 3    Primary            118 GB   117 MB
  Partition 4    Recovery           830 MB   118 GB

System partition

The device must contain a system partition. On GPT drives, this is known as the EFI System Partition, or the ESP. This partition is usually stored on the primary hard drive. The device boots to this partition.

The default size of the EFI partition is 100 MB (on advanced format disks with 4KB sectors the size of the EFI partition is 260MB), and must be formatted using the FAT32 file format.

This partition is managed by the operating system, and should not contain any other files, including Windows RE tools.

Microsoft reserved partition (MSR)

The size of the MSR is 16 MB, and the file system is NTFS.

The MSR partition must be between the EFI System partition (ESP) and the primary Windows operating system partition.

Add an MSR to each GPT drive to help with partition management. The MSR is a reserved partition that does not receive a partition ID. It cannot store user data.

Recovery tools partition

  • For Windows operating systems prior to Windows 10, version 2004 or Windows Server 2022:

    If the partition is smaller than 500 MB, it must have at least 50 MB of free space.
    If the partition is 500 MB or larger, it must have at least 320 MB of free space.
    If the partition is larger than 1 gigabyte (GB), it must have at least 1 GB of free space.

  • For Windows operating systems later than Windows 10, version 2004 or Windows Server 2022, the partition must have at least 200 MB of free space.

  • The partition must use the following Type ID:
    DE94BBA4-06D1-4D40-A16A-BFD50179D6AC

The Windows RE tools should be in a partition that's separate from the Windows partition. This separation supports automatic failover and the startup of partitions that are encrypted by using Windows BitLocker Drive Encryption.

BIOS/MBR-based hard drive partitions

If you install Windows using a bootable USB key made by Windows Imaging and Configuration Designer (ICD), it creates the following layout by default: a system partition, a Windows partition, and a recovery tools partition.

bios partition layout

DISKPART> list partition

  Partition ###  Type              Size     Offset
  -------------  ----------------  -------  -------
  Partition 1    System             100 MB  1024 KB
  Partition 3    Primary            118 GB   117 MB
  Partition 4    Recovery           650 MB   118 GB

System partition

Each bootable drive must contain a system partition. The system partition must be configured as the active partition.

In Windows 7/Windows Server 2008R2 the size of the System Reserved partition is 100 MB, in Windows 8.1/Windows Server 2012 R2 it is 350 MB, and in Windows 10/Windows Server 2016 it is increased to 500 MB.

Recovery tools partition

Create a separate recovery partition to support automatic failover and to support booting Windows BitLocker Drive Encryption-encrypted partitions.

We recommend that you place this partition in a separate partition, immediately after the Windows partition. This allows Windows to modify and recreate the partition later if future updates require a larger recovery image.