Problems to open downloaded .chm (help) files after security update installation

Problems to open downloaded .chm (help) files after security update installation

  
If you've installed Windows security update 896358 http://support.microsoft.com/kb/896358, you may experience a problem to open a downloaded compiled help module file (chm).
To solve this problem, Microsoft advises you http://support.microsoft.com/kb/902225/en-us to right-click the file that you want to open, click Properties, and then click Unblock.