I've been using the boxed build 1940 for several months. (Check for updates has never worked for me.) I'm usinga MacBook Black, 2Gh Core2Duo, 2GB RAM and 120 GB drive. OS X 10.4.8 My XP VM installation has worked well, but I thought I would upgrade to the newest release (hard for me to tell the betas from the Release Candidate, from an official Release, BTW.) I tried installing build 3188 over existing install as recommended. Rebooted the Mac and opened Parallels and started the VM (WinXPsp2.) Windows started to boot, and at some point an update video driver screen came up, I clicked yes, and shortly thereafter the VM went to a black screen. After several attempts to reboot, each time getting the Windows Logo then a black screen, restarting Parallels, I reinstalled Parallels from the CD (build1940) and everything worked normally. Then I came across this thread How to Upgrade Painlessly. I followed the 4 easy steps..... 1) Using the original version (1970) start each VM and uninstall Parallels tools using Add / Remove Programs. When the uninstall asks you to restart, just shut down. 2) After all VMs are modified, install 3186 over 1970 (no need to uninstall first). 3) Reboot the Mac. 4) Start each VM. Log in. Cancel any new hardware wizards. Install tools from the actions menu. When the tools install is complete, restart the VM. and got exactly the same results (but no prompt to upgrade a video or display adapter, this occurred only on the first attempt to boot after installing 3188.) Reinstalling build 1940 has my XP running again. Any thoughts? Am I doing something wrong?