The "Challenge Series" in Carbon is locked until you finish the first race in Career Mode. These challenges are how you unlock bonus cars (like the ’71 Dodge Challenger or the Koenigsegg CCX). A 0% save unlocks the Challenge Series menu from the start.
Sometimes "0% save" refers to a common technical issue where the game fails to record progress on modern systems. nfs carbon 0 save game
Update the save's internal "CD Key" to match your game's installation. The "Challenge Series" in Carbon is locked until
You downloaded the 0% save, placed it correctly, but the game says: "The save file is corrupted and cannot be loaded." placed it correctly