This would be a useful feature for my current situation where multiple designers are working on the same file. This would eliminate the possibility of copying over work performed on the file by another designer. I would appreciate any thoughts on this. May there is just a process that could be applied that I'm not considering? Maybe if you are opening directly from the cloud another user can't access the file? I've worked on share sites that have this process of checking in and checking out the file—you could also see who had the file open. It prevented a lot of head aches.