Shutting down seems to have fixed my problem, too. But then again build 1970 had appeared to fix it temporarily as well for a short while and then it came back. Like most people's experience, rebooting after the firmware upgrade did nothing, but shutting down did seem to work. Can Parallels somehow confirm with Apple whether they did include a fix for the VT-X problem in this latest EFI change? I'd hate to think this is just a temporary coincidence.