You know. . . I get this problem too. What I usually do is export the UV's from the model before this happens to it using Steve Cox's UV Mapper. Then if this happens I can just open the sucker up in UV Mapper again and re-apply the old UV's. There may be an easier way to do it, or something more straight forward, but it works. That works in the programs I use anyway. I don't have Max, so I don't know if it would work on a 3DS file. I don't think UV Mapper can open anything but OBJ.