WinUtilities Help Manual
File Format: .CHM
Microsoft Compiled HTML Help 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.
Q: Why chm viewer unable to show contents?
A: Try to right-click on your chm file and select properties. You will see an "Unblock" button. Click on it, it should solve your problem.