Chm File For Mac

If you are using windows or Linux OS then CHM files can be opened and viewed easily, but for MAC OS X users there is no extension which supports chm file reading which needs to be resolved. And if you are wondering what is a chm file then head over to this post. And if you’ve come here searching for CHM readers then read on.

  • Chm reader in mac free download. Cool Reader CoolReader is fast and small cross-platform XML/CSS based eBook reader for desktops and handheld dev.
  • IChm is a chm file reader for Mac OS X ###Developer Notes:### To build this fork of iChm (and its submodules), you’ll need at least Xcode 5.1 in OS X 10.9 (Mavericks).
  • CHM is a Microsoft Compiled HTML format used in help files. If you want to read the help files then you need a software which can read the CHM files. You can convert this into PDF file so that you can refer this anytime or send it across for people to read the PDF.

There are several chm viewing application for Mac OS X but some of them doesn’t work as it was intended too. For this reason here is a simple freeware Mac based chm reader which solves inconveniences that was caused with other chm readers and works perfectly well.

The chm file represents a collection of HTML documents and other data such as images and JavaScript compressed into a single file. These chm files contain a number of powerful features present in the specifications available here including: Table of Contents, Index of keywords and Full-text search functionality. Updated: April 22, 2020.

iChm reader is light weight easy .chm file reader for Mac OS X with a fully built cocoa that works faster compared to other chm viewing utility. The chm viewer has tabbed browsing feature and also easy search right on the top with text zooming option. The best feature is the easy navigation of back, forward, home, automatic search & easy to locate table of content.

iCHM reader is localized in 5 languages and it supports Mac OS X, so if you have a Mac OS X 10.5 or later version then get this chm reader for easy reading! 😉


Related posts:

Microsoft Compiled HTML Help
Filename extension
Internet media type
Developed byMicrosoft
Initial release1997
Latest release
Extended to.lit
Microsoft Compiled HTML Help
Operating systemMicrosoft Windows
PredecessorMicrosoft WinHelp
SuccessorMicrosoft Help 2
TypeHelp system

Microsoft Compiled HTML HelpTargus displaylink drivers. is a Microsoft proprietary online help format, consisting of a collection of HTML pages, an index and other navigation tools. The files are compressed and deployed in a binary format with the extension .CHM, for Compiled HTML. The format is often used for software documentation.

It was introduced as the successor to Microsoft WinHelp with the release of Windows 95 OSR 2.5[3] and consequently, Windows 98. Within the Windows NT family, the CHM file support is introduced in Windows NT 4.0[4][5][6] and is still supported in Windows 10.[7] Although the format was designed by Microsoft, it has been successfully reverse-engineered and is now supported in many document viewer applications.


February1996Microsoft announces plans to stop development of WinHelp and start development on HTML Help.
August1997HTML Help 1.0 (HH 1.0) is released with Internet Explorer 4.
February1998HTML Help 1.1a ships with Windows 98.
January2000HTML Help 1.3 ships with Windows 2000.
JulyHTML Help 1.32 releases with Internet Explorer 5.5 and Windows Me.
October2001HTML Help 1.33 releases with Internet Explorer 6 and Windows XP.
MarchAt the WritersUA (formerly WinWriters) conference, Microsoft announces plans for a new help platform, Help 2, which is also HTML based.
January2003Microsoft decides not to release Microsoft Help 2 as a general Help platform.

Microsoft has announced that they do not intend to add any new features to HTML Help.[8]

File format[edit]

Help is delivered as a binary file with the .chm extension. It contains a set of HTML files, a hyperlinked table of contents, and an index file. The file format has been reverse-engineered and documentation of it is freely available.[9][10]

The file starts with bytes 'ITSF' (in ASCII), for 'Info-Tech Storage Format'.[why?]

CHM files support the following features:

  • Data compression (using LZX)
  • Built-in search engine
  • Ability to merge multiple .chm help files
  • Extended character support, although it does not fully support Unicode.[11]

Use in Windows applications[edit]

The Microsoft Reader's .lit file format is a modification of the HTML Help CHM format. CHM files are sometimes used for e-books.[12]

Sumatra PDF supports viewing CHM documents since version 1.9.

Various applications, such as HTML Help Workshop and 7-Zip can decompile CHM files. The hh.exe utility on Windows and the extract_chmLib utility (a component of chmlib) on Linux can also decompile CHM files.

Microsoft's HTML Help Workshop and Compiler generate CHM files by instructions stored in a HTML Help project. The file name of such a project has the extension .HHP and the file is just a text with the INI file format.[13]

The Free Pascal project has a compiler (chmcmd) that can create CHM files in a multiplatform way.

Use in non-Windows applications[edit]

Read support:

  • GTK: GnoCHM on, CHMsee, chmviewkit
  • Qt: Okular, kchmviewer, KCHM on
  • Java: CHMPane on
  • iOS: CHMate Neue, iChm, ChmPlus, ReadCHM
  • Android: KingReader[permanent dead link], Chm Reader, iReader
  • Mac OS X: iChm (Discontinued), ChmPlus (Discontinued), CHMox(PowerPC apps no longer supported), ArCHMock (Discontinued), CHM to EPUB (Discontinued), Clearview Reader
  • Other / Cross-platform: xCHM, arCHMage on, DisplayCHM
  • Amiga: libmspack on Aminet

Read/write support:

  • Lazarus (IDE)/Free Pascal (for a doxygen like tool, a separate commandlinecompiler in 2.6.0+, and a simple viewer in Lazarus)

See also[edit]

The Wikibook Windows Programming has a page on the topic of: Compiled HTML Help


  1. ^Techtonik, Anatoly (11 April 2006). 'application/'. Retrieved 7 March 2012.
  2. ^'Microsoft HTML Help 1.4'. Windows Dev Center. Microsoft. Retrieved 10 January 2017.
  3. ^^ since IE 4 is bundled with OSR 2.5, hence adding the CHM file support for the first time^
  4. ^'Microsoft Security Bulletin MS02-055 - Critical'. Retrieved 2020-10-29.
  5. ^'Full Disclosure: HtmlHelp - .CHM File Heap Overflow'. Retrieved 2020-10-29.
  6. ^^ The information available is scarce, but any VM installation of WinNT 4.0 appears to give .CHM file support out of the box. It seems like it wasn't introduced in Windows NT 3.51 due to NT 3.51 being intentionally limited to Internet Explorer 16-bit versions^
  7. ^'[SOLVED] Windows 10 CHM Help Files showing up blank. - Spiceworks'. Retrieved 2020-10-29.
  8. ^'Microsoft HTML Help Downloads'. Microsoft. Retrieved 6 March 2012.
  9. ^Wise, Paul; Wing, Jed (2005). 'Unofficial (Preliminary) HTML Help Specification'. Retrieved 15 August 2012.
  10. ^Palade, Alexandru (2005). 'Archive::Chm'. Retrieved 22 July 2014.
  11. ^'INFO: Limited Unicode Support in HTML Help'. Microsoft. 11 April 2001. Archived from the original on 13 March 2016. Retrieved 17 March 2012.
  12. ^Title Handbook of Data CompressionAuthors David Salomon, Giovanni Motta, David (CON) BryantEdition 5, illustratedPublisher Springer, 2009ISBN1-84882-902-7, ISBN978-1-84882-902-2Length 1359 pages
  13. ^Wise, Paul; Wing, Jed (2005). 'Unofficial (Preliminary) HTML Help Specification INI formats'. Retrieved 1 February 2018.

Chm File Viewer Mac

External links[edit]

  • Microsoft Help 2 Reference (part of Visual Studio SDK for VS7.1 and VS8.0)
  • Unofficial (Preliminary) HTML Help Specification (the linked ITSF specification has been moved to the domain)

Chm File Mac Os X

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