I installed the latest built 1966 and even with the latest built, Parallels can't still handle more than 1 VM without stunting the activity of other VM. I have a Quad Mac Pro 2.66GHz with 5GB of memory and each XP has 500 MB of memory so there's plenty of free memory to spare. Has anybody experiencing the same? It would probably hose Parallels with 3 or more VM's. I guess Parallels is not yet mature enough to handle multi VM environments.