Open box in Illustrator not showing image

Im using Illustrator CS6 on a MAC (Yosemite) when I use the 'open' command in Illustrator my open  dialogue box looks like the attached. As you can see the image to the right is cut off and only partially viewable, I have tried all kinds of things but to no avail, its driving me nuts as I have to reference designs when I open them up in Illustrator.

Any ideas? 

Much obliged