Question: Hello, I am confused as to how the Halo Universal Binary works. I have the full, purchased Halo: PC version, and enjoy that on my PC, but cannot use its CD key to validate the purchase of the Binary. The instructions say that the update is intended for users who previously purchased the full game and would like to upgrade, but I do not know if by full game they mean PC or Mac versions, or just Mac. Thank you for your time.

Answer: Sorry, you cannot use the PC key to purchase the Halo Universal Binary. You must have the original Mac version in order to update to the Halo Universal Binary version.