Quite honestly, I don't know. I've never had the problem of a file that will not open except once. I then opened the backup file and it worked. I believe that when you save a file by hitting the 'save' button it will update the backup file as well. I could be wrong because I've never dealt with a problem like this. Perhaps someone from e-on can elucidate the answer for us. I do think that the file extension should always be .vue or .bak and not .01vue or .02bak Sorry I don't know more about the file system. MN