If the CHM Help file does not display the content in the right-hand panel, this is likely due to your computer blocking it.
To fix:-
1. Using Windows Explorer, locate the chm file. If you have downloaded it then it will likely be in your Downloads folder. If you have IRRICAD installed it will be located in the installed Help folder, commonly located at C:\Program Files (x86)\AEI Software\IRRICAD Pro 16\Help or C:\Program Files (x86)\Irricad\IRRICAD Pro 17\Help.
2. Right-click on the CHM file, and select Properties from the menu.
3. Immediately below the Advanced button on the General page is an "Unblock" option - click the box to enable.
4. Click Apply to show the content. Once the CHM file has been unblocked, the Unblock button disappears.
Now the content of the CHM should display properly.
The IRRICAD Team