One of the initial issues I had with Pro 18 was “where is the backup?” I couldn’t find it. It wasn’t in my folder with the rest of the files like it was with 13. THEN I found that there is a different method being used…and the backup files (NOT .BAK however) are held in a different folder.
I found that I needed to load an EMPTY project and Vegas would ask if I wanted to restore the previous version of my project. So far, seems to work.
There is an option to have the .bak file show up like it used to… LOTSA new stuff to learn – especially since I upgraded from 13.