While doing some database editing after testing the latest version 7.6 I discovered that batch update movie details changes the user's ratings and the genres without the user's permission (I have the button update "Actors and roles only" selected).
I noticed this when the program changed my rating (2 stars) for the Russian film "The Cranes are Flying" to the IMDB rating (4 stars). The box "Do not change ratings" is solid black and can not be changed by the user so I assume that means that ratings will not be changed (and why would they when I have checked the button "Actors and roles only".)
The program also added back genres I had eliminated from use for many films, e.g., history. I created my own genre "historical drama" to better describe many of these films but the program added "history" back to films where I had deleted that specific genre.
I can not recommend that anyone use the batch update movie details tool unless you have done absolutely no editing to any of your records. This tool is broken and will break your carefully edited database if you use it.