Some parts created by EDT when generating groups are empty. Should I delete them?

Once students have been assigned to all groups, some of the automatically created parts remain empty. These "potential" parts make it easier to change classes if necessary, but can be an additional constraints when it comes to placement (in particular for placing core courses on half-days when specialization courses take place).

If you consider that students will no longer change class, you can delete them: in the display Timetable > Specializations > Generation of the specialization groups, select the groups on the right, right-click and launch the command Delete parts without students from the groups.