I am running a late 2009 Mac mini (2.53 mhz; Core 2 Duo; 8 GB RAM) and a 2011 MacBook Pro. I purchased Mountain Lion last year when I bought both systems and have noticed that my Macbook Pro has updated to 10.8.4 while my Mac mini remains at 10.7.5. When I have checked for updates on my mini it says everything is up to date. When I have manually downloaded 10.8.4 and tried to update it states that I must have 10.8 on my system (which doesn't appear to exist). Looking for clues as to what to do.