LEGO Harry Potter Collection
84 Achievements
Steam
Halfway There
Unlocked on hitting 50% game completion (Single Player Only) (Years 5-7)
8.7%
How to unlock the Halfway There achievement in LEGO Harry Potter Collection - Definitive Guide
So this isn't unlocked until you have hit 50% in the whole game, that's years 1-4 and 5-7 so when you have hit 50% or more in both it will unlock
Complete 50% of LEGO Harry Potter: Years 5-7. See "But... I Am The Chosen One" for more information.