After installation of Microsoft security update MS05-026 (KB896358), CHM help file topics may not display correctly if the help file was downloaded from Internet. Instead, an error message such as "Action canceled" or "DNS error" is displayed.

Recent Microsoft security updates include changes to the InfoTech protocol, which prevent CHM help files from being displayed correctly if the CHM help file is blocked by Windows Attachment Manager. Even if the security warning is acknowledged, the help file is not displayed correctly. The problem also arises when a blocked CHM help file is opened via the HtmlHelp API.

This affects the download of EPiServer SDK.

Solution

To open a blocked CHM help file, follow the instructions below.

1. Double-click the help file in Windows Explorer.

2. If a security warning dialog appears, uncheck the box ‘Always ask before opening this file’.
3. Click Open to open the help file.

More information from Microsoft is available at After you install security update 896358, downloaded Compiled Help Module files cannot be opened.