I had KIS 2014 working fine in WIndows 8.1 but after I updated to Windows 8.1 update 1 , it is showing not active in action centre while the app is showing that it is protecting my PC ... The version is 14.0.0.4651(g) ... It even found a virus in a game crack file .. However , its more of the firewall that bothers me coz KIS firewall is much ( possibly way ) better than windows defender ... And another thing I saw when I opened Windows Defender is that it is showing win defender is on but it is managed by KIS ... I will try reinstalling Kaspersky , meanwhile any other suggestions are more than welcome ...