Booting Windows PE

Applies To: Windows 7, Windows Server 2008 R2


This content applies to Windows 7. For Windows 8 content, see Windows Deployment with the Windows ADK.

After creating a custom Windows® Preinstallation Environment (Windows PE) image, you must decide how the image will boot and where it will run from.

There are five methods of starting Windows PE by using a RAM disk. You can create bootable Windows PE RAM disk images on:

  • CD-ROM and DVD-ROM.

  • A USB flash drive (UFD).

  • A hard disk.

  • A Windows Deployment Services (Windows DS) server. You can access the image by using Pre-Boot Execution Environment (PXE) boot.

  • A supported PXE server. You can access the image by using PXE boot.

Normally, when you start a computer from a hard disk drive or a CD-ROM, Windows keeps operating-system file handles open and dedicated to that instance of Windows. Therefore, you cannot remove the CD that you used to start the computer. You cannot delete the hard disk partition from which you started the computer.

The small size of Windows PE enables the entire Windows PE operating system image to load into random access memory (RAM) and to start the computer from a RAM disk. The RAM disk boot feature provides a virtual CD file system in memory. Booting Windows PE from a RAM disk enables you to:

  • Swap the removable media (CD-ROM or DVD-ROM) that is used to start the computer and insert another CD-ROM or DVD-ROM to add drivers, utilities, applications, or a Windows operating system image.

  • Start the computer from a Windows Deployment Services (PXE) server with the ability to disconnect from the network once Windows PE has loaded. After the initial download of the Windows PE image, there are no longer any dependencies on network resources.

  • Delete and repartition the hard disk from which Windows PE has just started.

  • Decrease total boot time.


  • By default, Windows PE assigns X as the drive letter of any media that it boots from. You can change the drive location using DISM /Set-TargetPath.

  • For Unified Extensible Firmware Interface (UEFI)-based computers, you must start Windows PE by using the EFI boot-mode option in the EFI shell. For more information, see your EFI firmware documentation.

  • Requirements

    The following items are required for starting Windows PE by using a RAM disk:

    • An x86-based, x64-based, or Itanium-based computer.

    • A bootable Windows PE image created from a Windows PE 3.0 base image.

    • A minimum of 512 megabytes (MB) of RAM (when using the default Windows PE disk image).

    See Also


    Walkthrough: Create a Bootable Windows PE RAM Disk on CD-ROM