Hello, I'm a teacher. Our MIS department just updated my iMac lab to 10.9.5. My issue is I'm having issues updating my desktop iMac. I hung on to 10.8 because at the time I was using OSX Server and didn't want to gamble that it would work in controlling users and devices. Well, since now the MIS Dept is using their Active Directory servers, I no longer am worried about the updating my desktop OS. Another concern, I teach Video Production, using Final Cut Pro X. I am at a point of HAVING to update it to the same version as my classroom computer because I use a projector & Lanschool so I can model video editing as I teach. There's a big difference between the GUI of FCPX in Mountain Lion and Mavericks. So I used a Install Maverick USB that I had and updated mine to 10.9.1. So I figure go to the App Store and do an update to 10.9.5..... Not available.... So I figure go to apple support and find the 10.9.2-10.9.5 updates. Download them thinking all I have to do is install them.... But they are won't load... Any help and comments are welcome!