Viewing Downloaded CHM Files

HydroTel documentation is available in both CHM and HTML formats. CHM (Compiled HTML) is a Microsoft format. All modern versions of Windows include a CHM file viewer. CHM is recommended over HTML if the documentation is viewed on Windows, because CHM has built-in support for indexing, searching and bookmarks. 

CHM is based on HTML, and HTML can launch ActiveX controls so can be unsafe. If the CHM file is downloaded from Internet, either directly or in a zip file, Windows will require the user to "unblock" the CHM in order to view it properly. The following are the steps to view a downloaded CHM file: 

  • If the CHM file is in a zip file, unzip it first. It is not possible to unblock the CHM file without unzipping it. 

  • If you just double-click on the CHM file to open it, you get the "Navigation to the webpage was canceled" screen. 
  • To unblock the CHM file, right click on the file, select "Properties". Click on the "Unblock" button, then click "OK". 

  • You should now be able to view the CHM file.