For new installations, by default, Windows Setup will create an Extensible Firmware Interface System Partition (EFI System Partition, or ESP), a Microsoft® Reserved partition (MSR), and a primary Windows partition.

This table shows the partition structure:

	Note:
	In this example, the Windows partition is assigned the letter "W" to avoid drive-letter conflicts. After the computer reboots, the primary hard disk will automatically be reassigned to the letter "C".

Windows Setup creates an ESP on the computer when:

• There is no existing ESP.
  
  
• There is enough disk space to create a 100 MB partition.
  
  

Windows Setup creates the MSR when:

• There is no existing MSR.
  
  
• There is enough disk space to create a 128 MB partition.
  
  

Creation of the ESP takes priority over the MSR because the ESP is required to boot the computer.

When upgrading Windows from a previous version, Windows Setup does not change the arrangement of your partitions.

The code below shows a script for the DiskPart command that will create the default partition structure, for use in image-based deployments.

select disk 0
clean
convert gpt
create partition efi size=100
format quick fs=fat32 label="System"
assign letter="S"
create partition msr size=128
create partition primary
format quick fs=ntfs label="Windows"
assign letter="W"

Consider installing recovery tools such as Windows Recovery Environment (Windows RE) in a separate partition from the Windows partition, to enable end users to repair or reinstall Windows without deleting the recovery tools. If you install Windows RE, we recommend installing it to the system partition.

Once installed, you can configure Windows Boot Manager to fail over to recovery tool when Windows is unable to start.

To configure a separate recovery partition, identify the partition as a utility partition by setting the partition type:

• In Windows SIM, set: Microsoft-Windows-Setup\ DiskConfiguration\Disk\ModifyPartition\TypeID to de94bba4-06d1-4d40-a16a-bfd50179d6ac.
  
  
• In the DiskPart tool, after you have created and formatted the partition, use the command set id= de94bba4-06d1-4d40-a16a-bfd50179d6ac.
  
  We recommend placing recovery and utility partitions at the beginning of the drive. Recovery partitions do not appear in Windows Explorer.
  
  

In the example below, the configuration includes a primary recovery partition, an ESP, an MSR, and a primary Windows partition.

The table below shows settings used in Windows SIM, under Microsoft-Windows-Setup \DiskConfiguration\Disk, to set up this example configuration.

	Note:
	In this example, the Windows partition is assigned the letter "W" to avoid drive-letter conflicts. After the computer reboots, the primary hard disk will automatically be reassigned to the letter "C".

The code below shows a script for the DiskPart command that will create the example partition structure, for use with image-based deployments.

select disk 0
clean
convert gpt
create partition primary size=250

format quick fs=ntfs label="Recovery"
set id="de94bba4-06d1-4d40-a16a-bfd50179d6ac"
assign letter="R"
create partition efi size=100
format quick fs=fat32 label="System"
assign letter="S"
create partition msr size=128
create partition primary
format quick fs=ntfs label="Windows"
assign letter="W"

By default, the system partition and utility partitions do not appear in Windows Explorer. To confirm that these partitions exist on the destination computer, do the following:

1. Click Start, right-click Computer, and then click Manage. This opens the Computer Management control panel.
   
   
2. Click Disk Management. The list of available disks and partitions appears.
   
   
3. In the list of partitions, confirm that the system and utility partitions are present and are not assigned a drive letter.
   
   

• Understanding BitLocker Drive Encryption
• Deploy a System Recovery Image