Is there a way to recover a file that was not saved?

I had a file open that I was currently working on, and opened an old file to update info.  I saved changes in the older file, and closed the program.   When it asked me if I wanted to save the file, I said no thinking it was referring to the file I had just saved.  So, the current file was not saved.  It reverted to the last save showing no updates.  I tried to find a temporary backup file, but could not find one.