If you look at the URL of a help topic you see something like this: points at a special Microsoft Url Moniker that in turn points the CHM file and a relative path within that HTML help file. The reason this happens is because files downloaded off the Internet - including ZIP files and CHM files contained in those zip files - are marked as as coming from the Internet and so can potentially be malicious, so do not get browsing rights on the local machine – they can’t access local Web content, which is exactly what help topics are. Looks like a broken help file, right? But it's not - it's merely a Windows security 'feature' that tries to be overly helpful in protecting you.

The CHM file obviously opened since the topic list is there, but the Help Viewer refuses to display the content. The help file comes up with all topics in the tree on the left, but a Navigation to the WebPage was cancelled or Operation Aborted error in the Help Viewer's content window whenever you try to open a topic. She then opens the help file and finds the following unfortunate result: The customer downloads the file, opens the zip file and copies the help file contained in the zip file to disk. Or alternately you've created a help file and you let your customers download them off the Internet directly or in a zip file.

Here’s the scenario: You go ahead and happily build your fancy, schmanzy Help File for your application and deploy it to your customer.

As a publisher of a Help Creation tool called Html Help Help Builder, I’ve seen a lot of problems with help files that won't properly display actual topic content and displays an error message for topics instead.

Read chm file