Windows PE Overview

Applies To: Windows 8, Windows Server 2012

The Windows® Preinstallation Environment (Windows PE) is a minimal Windows operating system that includes limited services and is built on the Windows 8 kernel. You can use it to prepare a computer for Windows installation, to copy disk images from a network file server, and to initiate Windows Setup.

Windows PE isn't designed to be the primary operating system on a computer. Instead, it's used as a stand-alone preinstallation environment and as an integral component of other setup and recovery technologies. These technologies include Windows Deployment Services, Microsoft® System Center Configuration Manager, and Windows Recovery Environment (Windows RE).

In this topic:

• Supported Platforms

• Windows PE Releases

• Common Windows PE Scenarios

• Benefits of Windows PE

• Windows PE Dependencies

• Windows PE Limitations

Supported Platforms

The following table lists Windows PE operating systems and the architecture types that you can install them on.

Windows PE Releases

The following table lists the Windows PE release and the corresponding toolkit and operating system. The toolkit refers to the Windows OEM Preinstallation Kit (Windows OPK), Windows Automated Installation Kit (Windows AIK), or Windows® Assessment and Deployment Kit (Windows ADK).

To identify the Windows PE release that you are running

1. At a Windows PE command prompt, type regedit

2. Locate this registry key:

   HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\WinPE

   The Version registry value shows the Windows PE version.

Common Windows PE Scenarios

Windows PE is a modified version of the Windows operating system. It supports the installation of Windows and the troubleshooting and recovery of an installation that can no longer boot. Here are some details:

• Installation of Windows. Windows PE runs every time that you install Windows. The graphical tools that collect configuration information during the setup phase run within Windows PE. And, IT departments can customize and extend Windows PE to meet their unique deployment needs. Windows PE also provides support for servicing Windows images.

  Important

  Windows PE supports the deployment of earlier versions of Windows. For restrictions, refer to your Microsoft Software License Terms or contact your Microsoft representative.

• Troubleshooting. Windows PE is useful for both automatic and manual troubleshooting. For example, if Windows can't start because of a corrupted system file, Windows PE can automatically start Windows RE. You can also manually start Windows PE to use built-in or customized troubleshooting and diagnostic tools.

• Recovery. You can use Windows PE to build customized, automated solutions for recovering and rebuilding computers that are running Windows. For example, end users can boot their computers from a Windows PE recovery CD, a recovery DVD, or recovery partitions to automatically reformat their hard disks and to reinstall Windows 8 with the original drivers, settings, and applications.

Benefits of Windows PE

Windows PE was created to boot a computer that has no functioning operating system for deployment and recovery. You can build a single Windows PE image that you can then use to install both 32-bit and 64-bit versions of Windows. The benefit of using a cross-platform deployment solution is that you don't have to maintain multiple versions of Windows PE for installing Windows on different architecture types. For more information, see Windows Setup Supported Platforms and Cross-Platform Deployments and Limitations of cross-platform deployment. After you boot a computer in Windows PE, you can prepare it for Windows installation, and then initiate Windows Setup from a network or local source. You can also service an existing copy of Windows or recover data.

Because Windows PE is based on the kernel, it overcomes the limitations of MS-DOS®-based boot disks by providing these capabilities:

• Native support for the NTFS 5. x file system, including dynamic volume creation and management.

• Native support for TCP/IP networking and file sharing (client only).

• Native support for 32-bit (or 64-bit) Windows device drivers.

• Native support for a subset of the Windows application programming interface (API).

• Optional support for Windows Management Instrumentation (WMI), Windows Data Access Components (Windows DAC), and HTML Applications (HTAs).

• The ability to start from several media types, including CD, DVD, USB flash drive, and a Windows Deployment Services server.

• Support for offline sessions.

• Offline servicing of images.

• Inclusion of all Hyper-V™ drivers except display drivers. This enables Windows PE to run in a hypervisor. Supported features include mass storage, mouse integration, and network adapters.

Windows PE Dependencies

To function correctly, Windows PE relies on several Windows technologies:

• If you use Windows PE on a network, Dynamic Host Configuration Protocol (DHCP) and Domain Name System (DNS) servers are useful but not required.

• If you start Windows PE from a network, you must use Windows Deployment Services.

• If you install Windows, you must run Windows Setup (Setup.exe).

• If you automate a Windows 8 installation, you must use an answer file.

Windows PE Limitations

Windows PE is a subset of Windows 8 and has these limitations:

• To reduce its size, Windows PE includes only a subset of the available Windows APIs. It includes I/O (disk and network) and core Windows APIs.

• To prevent its use as a production operating system, Windows PE automatically stops running the shell and restarts after 72 hours of continuous use. This period is not configurable.

• Windows PE can't act as a file server or as a server that has Terminal Server enabled. (It doesn't support Remote Desktop.)

• Windows PE supports Distributed File System (DFS) name resolution for stand-alone namespaces only. It doesn't support domain namespaces. Stand-alone DFS namespaces allow for a DFS namespace that exists only on the local computer and therefore doesn't use Active Directory® Domain Services (AD DS).

• The supported methods of connecting to file servers are TCP/IP and NetBIOS over TCP/IP. Windows PE doesn't support other methods, like the Internetwork Packet Exchange/Sequenced Packet Exchange (IPX/SPX) network protocol.

• All changes that you make to the Windows PE registry while you're running Windows PE are lost the next time that you reboot the computer. To make permanent registry changes, you must edit the registry offline before you start Windows PE.

• Drive letters are assigned in consecutive order as you create partitions in Windows PE. But the drive letters revert to the default order when you restart Windows PE.

• You can use Windows PE to configure and to partition a computer's disks before Windows Setup starts. If any hard disks are converted to dynamic disks via Diskpart.exe before you start Windows Setup, those hard disks aren't recognized when the operating system is installed. Any volumes on those hard disks won't be available.

• Windows PE doesn't support applications that are packaged via Windows Installer (.msi) files.

• Windows PE doesn't support booting from a path that contains non-English characters.

• Windows PE does not include Windows 32-bit on Windows 64-bit (WoW64), Virtual DOS Machine (VDM), OS/2, or Portable Operating System Interface (POSIX) subsystems. Because Windows PE doesn't include WoW64, only native binaries can run on Windows PE. For example, only 32-bit Setup can run on 32-bit Windows PE.

Limitations of cross-platform deployment

Windows PE doesn't support these cross-platform scenarios:

• Installing a 64-bit Windows image on a 32-bit computer.

• Deploying a 32-bit Windows image from a 64-bit preinstallation environment.

• On Unified Extensible Firmware Interface (UEFI), deploying a 64-bit version of Windows from a 32-bit version of Windows PE.

• Using Windows PE boot files for an architecture that's different from the architecture of the computer that you're booting.

  For example, an x64-based UEFI computer can boot only by using Windows PE x64-based boot files. An x86-based computer can boot only by using Windows PE x86-based boot files. This differs from BIOS. In BIOS, an x64-based computer can boot by using x86-based boot files.

  Note

  On some UEFI computers, you can't install Windows in BIOS-compatibility mode and may have to switch to UEFI-compatibility mode. For more information, see How to Switch from BIOS-Compatibility Mode to UEFI Mode.

See Also

Concepts

Windows PE Process Overview
Booting Windows PE from RAM Disk
Building a Windows PE Image with Optional Components
Windows PE Tools

Other Resources

Windows PE Walkthroughs
Windows PE How-to Topics