Problem shutting down computer sometimes after 18.5 upgrade

After the recent 18.5 upgrade for my NIS2011, my computer has problem shutting down. The screen just stays at “Shutting Down” and never turns off. I’ve never changed or installed anything on my computer for quite some time already, so i’m sure it’s NIS2011 doing it. My computer runs vitsa32 and NIS is the only security software on it. Checked my windows log and no error showed up. It deosn’t happen all the time, i’d say 25% of the time it’ll fail to shut down properly.