I use several Virtual OS's with 3.0 on a 10.5.x MacBook. When I did the last upgrade to build 3382, my Vista complained that I had changed the hardware and therefore had to re-authenticate it. That's somewhat of a pain to have to go through whenever I upgrade between builds. So, now I see that there is a build 3384. If I upgrade to it, will I have the same problem with Vista? BTW, one other thing. Since moving to 3.0 last Fall, my installation has never told me that there is an update. I always accidentally find out that there is a new build after going to Parallels site.