Thanks for being so fast. I have build 5608. In both VM and opening Vista normally as primary OS, it says that Windows activation failed. I have Vista Home Premium, and microsoft said (I gave them a call) I'm not supposed to do that (use it on the same pc in both a VM and as primary OS. Only problem is I can't actually operate 2 lisecnces on the same mac, mostly because I am running Vista on the same machine, and even if I only use Parallels I have to install Vista with bootcamp. So?