Please ensure you have downloaded the correct version of 400 Days. When you purchase 400 Days, you will receive two download options: one for the physical disc version of the main game, and another for the digital version of the main game. Please download the version that corresponds with your copy of Season One:
- Download the Blu-Ray Version if you have The Walking Dead: Season One disc.
- Download the Digital Version if you have The Walking Dead: Season One digital download.
Please also ensure that both The Walking Dead and 400 Days are from the same region. For example, if you have a North American disc version of The Walking Dead, but the European digital version of 400 Days, they will not work together.