The problem is a change made when you installed security update 896358, which fixed a security vulnerability related to downloaded content blocks and blocks the ability to view some remote content. This limitation also affected downloaded HTML Help files, so you have to unblock the files.
There are two ways to resolve the invalid address error message:
- Double-click the .chm file. Next, in the Open File-Security Warning dialog box, clear the "Always ask before opening this file" check box. Then click Open; or
- Right-click the .chm file, and select Properties. Click Unblock. Then, double-click the .chm file to open the file.