error 102345

I save a backup file within the Document folder inside my computer. Today, I am ready to file, but ran into an issue.  Normally, I loaded the program the backup file would automatically load as well, but not this time.  So, I decided to load the file manually, but got an error code 102345.  I am frustrated as I spent numerous hours working on it.  Anyway suggestion that I can take to avoid a redo?

Thanks,
Long