My host operating system is OS X 11.6 El Capitan. I have tried installing a Mac Snow Leopard Server guest into Parallels Desktop Lite, but no matter how I configure it, if two CPU cores are allocated to the guest OS, they are both at 100% all the time when the guest is running - Activity Monitor in the host shows 200% for Parallels Desktop Lite. Needless to say, my Mac heats up quickly. I read and reread the knowledgebase article dealing with high CPU usage, and it advocated checking processes in the guest. No process in the guest was ever running higher than 0.9 or 1.0%. This includes all root and user processes. So that didn't explain it. I should mention, thought that the article was about a Windows guest. So I tried running the same virtual machine file in the trial version of Parallels Desktop. All the 200% issues disappeared. And Snow Leopard and Parallels are in Activity Monitor as 2 separate well-behaved processes. Snow Leopard at perhaps 20-25% CPU usage, Parallel Desktop at 5-9%. Totally acceptable, and even adjustable with the optimization control. Does anyone out there have any idea what could be going on here? Is there any hope of getting the Parallels Lite product to "behave"?