I have now upgraded to 4.0 four different VMs. I have two VMs one Vista and one XP and two fresh copies of those files as backup in case of infections These backups are just a fresh Windows installation and appropriate applications all registered. It does take time to do a backup and a conversion. All have run to successful completion. What I have noticed is particularly in Vista UAC does appear to be more aggressive and tougher to ignore when it finds new hardware. It is then confusing when UAC interferes with the new Parallels tools which have to be approved. I guess the message is when converting disallow or better yet ignore UAC request to install new hardware and only approve UAC requests for Parallels Tools.
