I saw somewhere that the copy protection scheme wasn't Mac-compatible. Don't know much about it though. As for the numbers of Mac/PC users it's not scientific but from the few threads I remember it seemed to be around 25-30% Mac users for Poser. Last time I looked at free items that were identicle & offered as PC version & Mac version it was almost 2 to 1 (or 50% Mac downloads VS 100% PC). That also held true for Carrara downloads.