Problem viewing help CHM files

Few minutes ago I downloaded Silverlight 3 documentation as CHM file so I can read it while I am offline. After I unzipped the file, I launched it to view silverlight documentation. I could not view the help content. Instead I got the following error message in the details view.

Navigation to web page was cancelled

I knew what this error was because lot of my HTML Parser clients have run into this issue and I have given them the solution. But I never took time to post the solution on the site to settle it once and for all. This actually is not an error or there is nothing wrong with the file itself. You see this behavior because of one of security patches introduced in Windows XP. Because of a security hole, hackers were able to exploit CHM files to introduce malicious piece of code into user's machines. So now when you download a CHM file from internet, the operation system knows that it came from internet zone so it blocks opening of this file. Here are the steps you will need to follow to view any CHM file that you download from internet.

1. Right click on the file and bring up properties of the file. You will see the following message at the bottom of General Tab

   

2. Click on Unblock button. You will see that warning message become gray.
3. Click on Apply button and you are done.

You should be able to view the help file now.