My boss and I share files on my computer with eachother. He was working on an Autocad file on his computer that was located on my computer when I restarted my computer. My computer froze while shutting down and then his computer froze while working on the Autocad file. After that, I am able to open files on my computer just fine, but my Boss cannot even open his Autocad anymore. The Autocad logo screen opens and says "Loading..." and then dissappears. We are both using macs and have been upgraded to the OSX Yosemite. How can I fix his computer to open the Autocad again??