Extract Raw Assets from CHM Files with 7-Zip

Yes, 7-Zip can open Compiled HTML Help (.chm) files and extract their raw assets directly. This guide explains how 7-Zip handles the CHM format, what types of assets you can retrieve, and the exact steps required to unpack web pages, images, and style sheets from any standard CHM archive on Windows.

Why 7-Zip Can Read CHM Files

Microsoft CHM files are proprietary archive containers based on the ITSF (InfoTech Storage Format) specification. Internally, they contain a compressed collection of standard web documents, images, and navigation files compressed using the LZX algorithm.

Because 7-Zip includes built-in support for the ITSF container format and LZX decompression, it treats .chm files just like standard .zip, .7z, or .tar archives. You do not need third-party decompilers or the Windows command-line utility hh.exe to inspect or extract the internal components.

Assets You Can Retrieve

When you unpack a CHM file using 7-Zip, you get direct access to all the original web assets used to build the help document:

  • HTML/HTM documents: The actual content pages containing text, tables, and hyperlinks.
  • Image files: Embedded graphics such as PNG, JPEG, GIF, and BMP formats.
  • Styling and Scripts: External CSS style sheets and JavaScript files.
  • Internal Help metadata: System files used by Microsoft HTML Help Workshop, including the table of contents (.hhc), the index file (.hhk), and project definition files.

How to Extract a CHM File Using 7-Zip

You can extract the contents using either the Windows context menu or the 7-Zip File Manager interface.

Method 1: Windows Context Menu (Quickest)

  1. Locate the .chm file in Windows File Explorer.
  2. Right-click the file and navigate to the 7-Zip submenu.
  3. Select Extract to "[Filename]".
  4. 7-Zip will create a new folder with the same name as your CHM file and extract all internal files while maintaining the original directory hierarchy.

Method 2: 7-Zip File Manager (Browse and Selective Extraction)

  1. Open 7-Zip File Manager.
  2. Navigate to the folder containing your target .chm file.
  3. Double-click the .chm file to open it as a virtual folder.
  4. Browse the contents to inspect specific files or subfolders.
  5. Select the specific assets you need, click the Extract button on the toolbar, choose an output destination, and click OK.

Additional Considerations

  • Hidden System Files: 7-Zip will also display internal system objects (such as #SYSTEM, #STRINGS, and #TOPICS). These binary files contain indexing information generated by the CHM compiler and can generally be ignored or deleted if you only need the website assets.
  • Security Blocks: If a CHM file was downloaded from the internet, Windows might block it by default. While this affects the native Windows CHM viewer, 7-Zip can still read and unpack the files regardless of the block status.