Create an Answer File for UEFI-based Computers

There are additional considerations to be aware of when creating an answer file for UEFI-based computers. Additional partitions are required for UEFI computers. These partitions need to be created during the unattended installation. In addition, you must boot to x64 EFI-mode preinstallation media (x64 Windows PE in EFI mode or x64 Windows Setup in EFI mode). You cannot install Windows to UEFI-based computers in BIOS mode.

For UEFI-based computers, each bootable drive must contain a Unified Extensible Firmware Interface System Partition (ESP) and at least one partition that contains an operating system. In addition, Microsoft strongly recommends that all GPT disks include a Microsoft Reserved Partition (MSR). This partition is used by Windows to store metadata outside of the Windows volume.

For more information about GPT disks, EFI, and hard disk partitions, see The Windows and GPT FAQ.

To Create Additional Partitions for the ESP and MSR

  1. Create a new answer file or update your existing answer file.
    For more information about creating or updating an answer file, see Work with Answer Files in Windows SIM.

  2. Add the following settings to your answer file in the listed configuration pass:

Setting Configuration Pass

Microsoft-Windows-Setup/DiskConfiguration

1 windowsPE

Microsoft-Windows-Setup/ImageInstall/OSImage/InstallTo

1 windowsPE

  1. In the answer file pane, in the Microsoft-Windows-Setup component, right-click DiskConfiguration and select Insert New Disk.

  2. First, create the different disk configurations required for UEFI. Configure the following settings in the Disk node:

Setting Value

Microsoft-Windows-Setup/DiskConfiguration/Disk

DiskID=0

WillWipeDisk=true

  1. In the answer file pane, in the Microsoft-Windows-Setup component, right-click CreatePartitions and select Insert New CreatePartition. Repeat this step two more times so that there are three CreatePartition entries in your answer file.

  2. Configure the following settings in the CreatePartition nodes:

Setting Value

Microsoft-Windows-Setup/DiskConfiguration/Disk/CreatePartitions/CreatePartition

Order=1

Size=200

Type=EFI

Microsoft-Windows-Setup/DiskConfiguration/Disk/CreatePartitions/CreatePartition

Order=2

Size=128

Type=MSR

Microsoft-Windows-Setup/DiskConfiguration/Disk/CreatePartitions/CreatePartition

Extend=true

Order=3

Type=Primary

The first `CreatePartition` setting creates the UEFI System Partition. The second `CreatePartion` creates the MSR, and the third `CreatePartition` setting creates the partition for Windows. Because the value for Extend is true, the remainder of the disk is used for the Windows partition.  
  1. Because partition 3 will be used as the Windows partition, you must specify the correct partition in the InstallTo/PartitionID setting. Configure the following settings in the InstallTo node.
Setting Value

Microsoft-Windows-Setup/ImageInstall/OSImage/InstallTo

DiskID=0

PartitionID=3

You can now use your updated answer file to deploy to a UEFI-based computer.  

Sample Answer File Snippet

The following sample answer file shows how to erase the disk and create the ESP, MSR and Windows partitions.

<DiskConfiguration>
   <Disk wcm:action="add">
      <CreatePartitions>
         <CreatePartition wcm:action="add">
            <Type>EFI</Type> 
            <Size>200</Size> 
            <Order>1</Order> 
         </CreatePartition>
         <CreatePartition wcm:action="add">
            <Order>2</Order> 
            <Size>128</Size> 
            <Type>MSR</Type> 
         </CreatePartition>
         <CreatePartition wcm:action="add">
            <Extend>true</Extend> 
            <Order>3</Order> 
            <Type>Primary</Type> 
         </CreatePartition>
      </CreatePartitions>
      <WillWipeDisk>true</WillWipeDisk> 
      <DiskID>0</DiskID> 
   </Disk>
</DiskConfiguration>
<ImageInstall>
   <OSImage>
      <InstallTo>
         <PartitionID>3</PartitionID> 
         <DiskID>0</DiskID> 
      </InstallTo>
   </OSImage>
</ImageInstall>

See Also

Concepts

Apply a Windows Image to UEFI-based Computers