This is a second attempt to reply to your comment, Sean. I got a message saying I did not have the sufficient authorization to do so--perhaps because I did not click the "Reply" button on your message. So I logged in again to see what happens this time.
I think you identified the problem. The file was file.nb~, and the tilde was apparently sufficient to frustrate the correct loading of the file.
I should have suspected this. Removing the tilde by copying the file to another with the .nb extension allow the correct loading. My operating system is MacOS 10.9.3 (Maverick),. Thanks for your comment.