Windows® Setup installs the Windows operating system. Windows Setup uses a technology called Image-based Setup (IBS) that provides a single, unified process with which all customers—including OEMs, corporations, and retail customers—can install Windows. IBS performs clean installations and upgrades of Windows and is used in both client and server installations.

Windows Setup also provides the capability to customize Windows during installation by using unattended Setup settings.

In This Section

Windows Setup Benefits

Windows Setup provides a quick and convenient way to install Windows. By reducing deployment and installation time, OEMs can reduce manufacturing costs, and corporations can more easily deploy Windows throughout their organization.

Windows Setup Features

Windows Setup includes several features that facilitate faster and more stable installations.

  • Faster installations and upgrades. Because Windows Setup is image-based, you can install and upgrade Windows faster and more easily. You can perform a clean installation by deploying the Windows image to destination computers. You can also perform quick and easy upgrades by installing a new image onto an existing Windows installation. The previous Windows settings are protected during the installation.

  • Better stability. Windows Setup uses Image-based setup technology that improves the stability and consistency of a Windows installation. It uses a file-based image, called a Windows image (.wim) container, for installation.

  • Improved Windows image management. Windows images are now stored in a single .wim file. A .wim file can store multiple instances of the Windows operating system in a single, compressed file.

  • Streamlined installation. Windows Setup is optimized to enable the manufacturing and deployment scenarios used by OEMs and corporations. As a result, installation takes less time, with fewer tasks to finish before installation is complete.

Common Installation Scenarios

Common installation scenarios include performing clean installations, upgrades, and unattended installations.

Custom Installations

The most common scenario for Windows Setup is performing a custom installation. In this scenario, you install Windows onto a computer that does not have an operating system, or has a previous version of Windows. This scenario consists of the following stages:

  1. Run Setup.exe from your Windows product DVD or network share.

  2. Select the Custom installation type.

  3. If you are installing from a previous installation of Windows, Windows Setup creates a local boot directory and copies all of the required Windows Setup files to this directory.

  4. Windows Setup reboots, installs and configures Windows components, and, after installation is complete, launches Windows Welcome.

Custom installations do not migrate any settings or preferences from previously installed versions of Windows. Files from previous Windows versions are copied to a \Windows.old directory. All data from the Windows installation including the Users, Program Files, and Windows directories are saved to this directory


Windows Setup can also perform upgrades from a supported operating system.

This scenario includes the following stages:

  1. Run Setup.exe on the previous version of Windows.

  2. Select the Upgrade installation type. Windows Setup upgrades the system and protects your files, settings, and preferences during the installation process.

  3. Windows Setup reboots and restores your protected files, settings, and preferences. Windows Setup then launches Windows Welcome.


Upgrades are used to upgrade a single computer to Windows® 7. Windows 7 also supports migrating user data to a new system.

Automated Installations

Automated installations enable you to customize a Windows installation and remove the need for a user to interact with Windows Setup. By using Windows System Image Manager (Windows SIM) or the Component Platform Interface (CPI) APIs, you can create one or more customized Windows installations that can then be deployed across many different hardware configurations.

The automated installation, also called an unattended installation, scenario includes the following stages:

  1. Use Windows SIM or the CPI APIs to create an unattended installation answer file, typically called Unattend.xml. This answer file contains all of the settings that you configure in the Windows image.

  2. From Windows PE, a previous version of Windows, or another preinstallation environment, run Setup.exe with the explicit path to the answer file. If you do not include the path to the answer file, Setup.exe searches for a valid answer file in several specific locations. For more information, see How Windows Setup Works.

  3. Windows Setup then installs the operating system and configures all settings listed in the answer file. Additional applications, device drivers, and updates can also be installed during Windows Setup. After the operating system is installed, Setup launches Windows Welcome.

Windows Setup Best Practices

The following section describes some of the best practices to use with Windows Setup.

  • Verify that there is enough space for Windows Setup temporary files. If you install Windows from a previous version of Windows, such as Windows XP, verify that there is enough space on the disk for temporary Windows Setup files. The space required may vary, but it can be up to 500 megabytes (MB).

  • Previous Windows installations are moved to a Windows.old folder. If you install Windows over a previous Windows installation, all previous Windows files and directories are moved to a Windows.old folder, including the contents of the Users, Program Files, and Windows directories. You can access your data in the Windows.old folder after Windows Setup completes. If you have additional folders not in the Users, Program Files, or Windows directories, those folders are not moved. For example, if you have a folder called C:\Drivers, that folder will not be moved to the Windows.old folder. As a best practice, you should back up your data before you upgrade.

  • Review the Windows log files. If you experience problems during Windows Setup, review the log files in %WINDIR%\panther. You will be able to identify and troubleshoot many issues by reviewing the installation log files. For more information, see Windows Setup Installation Process.

Windows Setup Limitations

The following sections describe some of the limitations of Windows Setup. Review this section before running Windows Setup.

  • Enable EFI mode to install to an EFI-based computer. If you are installing Windows to an EFI-based computer, you must enable EFI mode in the computer's firmware in both attended and unattended installations. You must boot to 64-bit EFI-mode preinstallation media (64-bit Windows PE in EFI mode, or 64-bit Windows Setup in EFI mode). You cannot install Windows to UEFI-based computers in BIOS mode. 

  • Applications might require a consistent drive letter. If you install custom applications to your Windows image, we recommend that you install Windows to the same drive letter on the destination computer because some applications require a consistent drive letter. Uninstallation, servicing, and repair scenarios might not function appropriately if the drive letter of the system does not match the drive letter specified in the application. This limitation applies to both the ImageX tool and Windows Setup.

  • Deploying multiple images to multiple partitions. If you capture and deploy multiple images on multiple partitions, the following requirements must be fulfilled:

    • The partition structure, bus location, and number of disks must be identical on the reference and destination computers.

    • The partition types (primary, extended, or logical) must match. The active partition on the reference computer must match that of the destination computer.

  • Installing Custom .wim files requires a description value in the .wim file. When you create a custom .wim file, Windows Setup requires that you always include a description value . If a .wim file does not include a description value, the image may not install properly. You can provide a description value when you use the imagex command with the /capture option. If you install a .wim file that does not have a description value, recapture the image and provide a valid description value. For more information, see the ImageX Technical Reference.

Technologies Related to Windows Setup

Windows System Image Manager

With Windows System Image Manager (Windows SIM), you can customize Windows images and their settings. You can select the settings you want to configure and then create an answer file to automate your installations. This answer file is used during Windows Setup to apply your configurations to Windows. In the answer file, you can specify changes to default operating system components and add software such as drivers or product updates. For more information, see Windows System Image Manager Technical Reference.

System Preparation Tool (Sysprep)

The Sysprep tool prepares a Windows installation for disk imaging, system testing, or delivery to a customer. Sysprep can be used to remove system-specific data from a Windows image, such as the security identifier (SID). After removing unique system information from an image, you can capture that Windows image by using a separate utility, such as the ImageX tool, and use it to deploy on multiple computers. In addition, the Sysprep tool can configure the Windows image to boot to audit mode or Windows Welcome. Audit mode enables you to test the integrity of the operating system and to install additional applications and device drivers. Windows Welcome is the first user experience that enables end users to customize Windows. For more information, see Sysprep Technical Reference.

Unattended Installation Answer File

An answer file is an .xml file that you can create by using Windows SIM. The answer file enables configuration of initial Windows settings as well as the addition of drivers, software updates, and other applications. The answer file enables you to customize Windows Setup parameters, such as specifying disk configurations, and language settings. Answer files are also used to customize the Windows operating system configurations. For example you can change the default values in Internet Explorer®, add device drivers, and configure Windows Firewall settings.


For Windows Vista®, Windows 7, Windows Server® 2008 and Windows Server® 2008 R2, the single answer file replaces all answer files that Windows XP used: Unattend.txt, Winbom.ini, Oobeinfo.ini, and Sysprep.inf. In addition, the Oobe.xml content file is used to configure Windows Welcome.

Windows Deployment Services

Windows Deployment Services is a network-based installation server that enables corporations to remotely administer and to deploy the latest operating system by using Windows PE and Windows Deployment Services server. This deployment scenario can be fully automated and is customizable and scalable. For more information, see Deploy Windows Using Windows Deployment Services.

Windows Preinstallation Environment

Windows Preinstallation Environment (Windows PE) is a minimal Win32® deployment environment. You use Windows PE to boot a computer without an operating system. By default, Windows PE runs in RAM. For more information, see Windows PE Technical Reference.


ImageX is a command-line tool that enables the capture, modification, and application of file-based Windows images (.wim) for deployment. For more information, see ImageX Technical Reference.

See Also