Norton Internet SEcurity 2014 keeps needing to download 241 MB.

4ellow icon has green check but when I manually run Live update sometimes it needs to download 241 MB.  How can it have a green check if it needs to download that much.  Is my computer safe?  If not why does it have the green check?

 

As noted: Using Norton Interent Security 2014.  The 241 download happens maybe once a month.  Your help is appreciated.