I spent about six hours composing this picture yesterday.  Did a test render at about 1AM and the render was great, just needed a couple of tweeks, so I saved it using the default and it saved as a .duf in my files.  I opened it about two hours ago and this is what I had.  The error message said it couldn't find some of the file links, but they were there when I saved the image, closed the program, and turned off the computer.

This isn't the first time this has happened, but I can't figure out how to fix it.

Anyone have any suggestions?