Our users are having an issue where as they are modeling they notice that even though they are on shaded view it starts becomming transparent then they will receive a fatal error. The first time we saw this was in July and at the time it was only one user and only while he was working in a family. Since then we've seen this on 3 users and in a working file. Sometimes you have the option to save as and exit. Other times you do not get the option to save. I have attached some images to this to show you exactly what is going on. All the images are in Shaded view as you will see. Our computers have 4GB of Ram not using the 3GB switch and are nvidia video cards. Any thoughts or help would be greatly appreciated. Thanks