Windows Image Files and Catalog Files Overview

Windows System Image Manager (Windows SIM) uses Windows image (.wim) files and catalog (.clg) files to display the available components and packages that can be added to an answer file (Unattend.xml). Windows images and catalog files contain configurable settings that you can modify after the component or package is added to an answer file.


Install.wim is located in the Sources folder of your Windows Installation Media download. See OEM deployment of Windows 10 for desktop editions for steps to make and deploy Windows images.

You can open Windows SIM by searching your computer for "Windows System Image Manager".

Supported architectures

Windows SIM can create catalog files for Windows images of the following architecture types

Your version of Windows Windows images you can create catalog files from

x86 version of Windows

x86-based systems, x64-based systems, and Arm-based systems

x64 version of Windows

x64-based systems only

Don't have an x86 PC handy?

  • You can install the 32-bit version of Windows on a 64-bit PC.
  • You can install Windows on a 32-bit virtual machine from a 64-bit PC.

Windows Image Files

A Windows image file contains one or more compressed Windows images. Each Windows image in a Windows image file contains a list of all of the components, settings, and packages that are available with that Windows image.

Limitations of Windows Image Files

The following list describes some of the limitations of using Windows image files:

  • Only an account that has administrator permissions can open Windows image files.
  • Only one user at a time can open Windows image files.
  • Because Windows image files can contain one or more Windows images, they are frequently large. Some Windows image files can be several gigabytes in size.
  • Because Windows images can be modified through different settings, using a Windows image file to create your answer file might cause you to apply altered default settings and configurations to a recaptured Windows image.

Because of these limitations, Windows SIM uses catalog files to create an answer file.

Catalog Files

A catalog file is a binary file that only includes the settings and packages in a Windows image. Catalog files (.clg) are only used by Windows SIM and is not used by other deployment tools, nor is it required to install Windows. When Windows SIM creates a catalog file, it queries the Windows image for a list of all the settings and state of each setting in that image. Because the contents of a Windows image can change over time, you must re-create the catalog file whenever you update a Windows image.

Because only administrators can open Windows images, you must have administrator permissions on the system to create a catalog file.

When Windows SIM opens a Windows image file or catalog file, all of the configurable components and packages inside that image are displayed in the Windows Image pane. You can then add components and settings to an answer file.

Contents of a Catalog File

A catalog file contains the following information:

  • A list of component settings and current values
  • Windows features and package states

Benefits of Catalog Files

Catalog files have several advantages over Windows image files:

  • The size of a catalog file can be less than 1 megabyte (MB), whereas the size of Windows image files can be several gigabytes. Also, catalog files are easier to copy to removable media or a network share.
  • Multiple users can create answer files for a single catalog file at the same time, whereas only one person can open and access a Windows image file at any particular time.
  • Non-administrators can create answer files for a catalog file. However, only administrators can open Windows image files.


  • "The catalog file for Windows Image (image name) cannot be opened for the following reason:

    Cannot find the catalog file associated with the Windows image (image name)

    You must have a valid catalog file to continue. Do you want to create a catalog file?"

    Fix: Click Yes to create a catalog file. After you've created the catalog file, this message will no longer appear.

    What's going on: This message usually shows up the first time you open a .wim file.

  • "Access denied"

    Fix: Copy the .wim file to a simple writable file location, like C:\Images, then try again.

    What's going on: This message appears when you're creating a catalog file from a .wim file that's in a location that the system can't write to, like a DVD or secured network share.

  • "Catalog creation failed to complete. This 64-bit version of Windows SIM can only create catalogs for 64-bit Windows images. For a list of supported architecture types, see link below."

    Fix: Use an x86 version installation of Windows to create catalog files for x86 or Arm-based .wim files.

    What's going on: Windows SIM can't create x86 or Arm catalog files from a 64-bit Windows installation.

Open a Windows Image or Catalog File

Windows System Image Manager Overview Topics