|This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)|
CHM files are single files, compressed and indexed HTML (CHM files can be extracted to a set of HTML and supporting files).
They are often used for an application's help.
Since a relatively recent windows security update, CHM files cannot be opened across a network (on UNC path or mapped drives. Web servers may also be limited, depending on how the file is actually opened), and the attempt to load their content tends to show "Navigation to the webpage was canceled".
If you trust specific sites, or trust your entire LAN, you can tell each computer to disable the related security measures(verify).
- ...and others.