SE IV had a generic race folder which files were used if you didn't have a certain race from a savegame you uploaded or if a certain image was lacking in a race folder.
This is lacking in SE V!
If you have a savegame which contains a race you don't have you are unable to open this savegame in SE V.
If as I hope a lot of new races will be published that might created a lot of problems and exclude the easy transfer of savegames from one player to another.
As an example I have a game where I use the new Ngrath race and encountered a bug. If I send the savegame to MM he will not be able to open the savegame unless he has this race too.