When you download a 100% save file, you aren't just getting a finished story mode. You are unlocking every corner of the game’s database. Here is exactly what a true 100% save file provides:
You downloaded a save from a different game version (e.g., a European save on a US copy). Fix: Use a hex editor or a "Save Game Converter." There are community tools that change the region code embedded in the .sav file. nfs carbon save game 100