In some cases the Browser Configuration Wizard from Kaspersky Internet Security 2012 may inform you on the Problems search completed step in the Additional Actions sections that you can eliminate the following problem: "Windows Explorer: display of known file types extensions is disabled".
In order to resolve the problem, perform the following actions:
Step 1. On the Browser Configuration Wizard, click on the Cancel button.
Step 2. Disable the option Hide extensions of known file types. In order to do this, perform the following actions: