I upgraded from B5 to B6. Contrary to a number of other testers, it didn't ask me to reboot the Mac (MBP - 2G ram - all Mac software up to date). Starting Parallels got me some odd warning messages (implying that another instance of a VMM was still running and that the CPU was in VM mode and that if the other VMM issued a vmexit this could mess up Parallels). I figured that rebooting the Mac was the safest route and did that. I started Parallels, started a VM (running XP Pro SP2 with all fixes, created with B1 and upgraded from there up to B5 and now to B6), installed the new tools. At the end of that install I was asked to reboot XP and got the BSOD :-( -- the messages flashed by too quickly to actually capture the cause. Here's an idea... can Parallels detect a BSOD and capture the output? That might be useful... Anyway, just letting you know. /D