The update box, that's icon gets thrown down into the Systray in the corner of the screen, should have an option to Cancel on it, doesnt it?   Worst case would be having to run Repair Updates if it didnt download or install properly, so Im not afraid of canceling an update 

Mine had already downloaded, but as I was in the middle of using the program it popped up with a little box in the right hand corner telling me that Updates were ready to Install, but I couldnt get them to install when I clicked on it.