I suspect either method would work. I have not yet upgraded to Parallels 4, so have not actually tested the method suggested to me by tech support. I was so surprised that they gave it to me for free that I posted it online for all to review. The official KnowledgeBase method is certainly cleaner than mucking about too much in the innards of Parallels. It sounds, based on observed experience (albeit limited), that the install process is flawed and would give an error regardless of whether the virtual machine was shut down properly or not. However, I will try the process myself before coming to any particular conclusions.