If there are both 32-bit and 64-bit Windows editions in a .wim file, you must choose which Windows image to install. Typically, the product key you specify in the ProductKey setting is used to determine which Windows image to install. However, if there are two instances of the same Windows edition - for example, Windows 7 Ultimate 32-bit and Windows 7 Ultimate 64-bit - you must specify which version to install. You can use the MetaData setting in an answer file to select the index number of the edition you want to install from the image file. For more information, see the Windows® Unattended Setup Reference.

The MetaData setting is used to specify which image to install. Use the ImageInstall\OSImage\InstallFrom\Metadata Key and Value settings in the Microsoft-Windows-Setup component to specify which Windows image to install. For example, if there are two versions of the Windows Vista Ultimate for different architecture types in a Windows image—for example, the 32-bit edition of Windows Vista Ultimate and the 64-bit version of Windows Vista Ultimate—you must specify metadata that corresponds to the image index, the name, the description, or the architecture type. For the architecture type metadata, use 0 for 32-bit and 9 for 64-bit. For more information, see the MetaData setting in the Windows® Unattended Setup Reference.

The answer file must include processor-specific components. The answer file settings in the windowsPE configuration pass must match the architecture type of the preinstallation environment and the settings that apply to the Windows image must match the architecture type of the image. For example, if you are creating an answer file that deploys 64-bit images from a 32-bit preinstallation environment, all components in the answer file for the windowsPE configuration pass must include the processor type attribute of x86. Settings to be applied in the specialize, oobeSystem, or other configuration passes must include the processor attribute type of amd64.

In 64-bit installations, all device drivers must be signed. In cross-architecture deployments, you can install an out-of-box device driver. However, if you install an unsigned out-of-box device driver in a 64-bit installation, it might result in an unusable installation. Unsigned boot-critical drivers will result in an unusable computer. Unsigned non-critical drivers will result in the device not being usable. All drivers included with Windows are signed. For more information, see Understanding Device Drivers and Deployment.

You can install 64-bit drivers to a Windows image during Windows Setup in one of the following ways:

• In attended installations, you can press F6 at the Disk Configuration page of Windows Setup, or click the Load Driver button..
  
  
• In unattended installations, use the Microsoft-Windows-PnpCustomizationsWinPE or Microsoft-Windows-PnpCustomizationsNonWinPE component in an answer file to specify a driver path. For more information, see the Windows® Unattended Setup Reference.
  
  

• Cross-platform installation to an iSCSI-based boot disk is not supported.
  
  
• Cross-architecture installations should only be used in factory deployment, Windows Deployment Services deployments, and clean-installation scenarios. OEMs should not provide cross-architecture installation media to end users for recovery or reinstallation. End users could install the wrong version of Windows for the architecture of their computer. In addition, the Windows Recovery feature included on the media would only apply to 32-bit Windows installations.
  
  Also, upgrade scenarios using a 32-bit version of Windows Setup to install a 64-bit operating system are blocked.
  
  
• Only x64 (AMD64) Windows editions are supported from 32-bit preinstallation environments for cross-architecture deployments. Cross-platform deployments of Itanium-based Windows images are not supported. Additionally, deploying a 32-bit image from a 64-bit preinstallation environment is not supported.
  
  
• Cross-platform deployments of multilingual Windows images that require language-pack installations are not supported. 32-bit language packs cannot be installed onto 64-bit Windows images. For cross-platform installations, language-pack package "Add" actions are ignored because the architecture of the language pack must match the architecture of the Windows image. We recommend that language packs be installed to the offline Windows image before deployment.
  
  
• Installing a 64-bit Windows image to a 32-bit computer results in an unsuccessful installation. Ensure that you are installing 64-bit Windows images on 64 bit–capable computers.
  
  
• When you install a 64-bit version of Windows from a 32-bit version of Windows PE, you must use Windows PE 2.0 or Windows PE 3.0. Cross-platform installations are supported only by these two versions of Windows PE. Previous versions of Windows PE do not support cross-platform installations.
  
  

• How Windows Setup Works