When you open a Windows® image (.wim) file in Windows System Image Manager (Windows SIM), a catalog (.clg) file is automatically created. If a catalog file already exists, Windows SIM re-creates the catalog file based on the contents of the Windows image that you select. When a catalog file is created, it queries the Windows image for a listing of all of the settings in that image.

A catalog file is a binary file that lists all the settings in a Windows image (.wim) file. Catalogs are smaller and more portable than Windows image files. For example, catalogs are typically less than 1 MB, while Windows image files can be several GBs in size or more. Due to their smaller size, catalog files can be easily copied to removable media, shared to a network folder, or sent as attachments in e-mail. Catalog files can also be opened by users who are not administrators. More than one user can open a catalog file at a time.

The Windows retail DVD includes pre-generated catalog files for each Windows image inside Install.wim. These catalog files are in the Sources directory of the retail DVD and can be used to create an answer file for a Windows image in the default Install.wim file. However, if you intend to create a catalog file for a custom Windows image, you should use Windows SIM to re-create the catalog file for that custom Windows image.


Because the contents of a Windows image can change over time, it is recommended that you re-create the catalog file periodically.

To create or re-create a catalog file

  1. Open Windows SIM.

  2. Open a Windows image. For more information, see Open a Windows Image or Catalog File

  3. On the Tools menu, click Create Catalog.

    The Open a Windows Image dialog box opens.

  4. Select a Windows image (.wim) file, and then click Open.

    If you choose a Windows image file that has more than one Windows image, the Select an Image dialog box opens.

  5. Click to select an image type (for example, Windows® 7 Ultimate), and then click OK.

    The catalog file is created in the same directory as the .wim file that you selected.


Windows SIM cannot create catalog files for some Windows images of different architecture types. For information about the cross-platform catalog creation support, see Understanding Windows Image Files and Catalog Files

See Also