I have noticed for some time that Parallels running Windows 7 is causing my mac to get very warm and consequently the fan to operate at high speed. This has the consequence that parallels flattens my battery within less than an hour. I have just upgraded to version 12 in the hope that this would address the issue however it is still continuing. Any suggestions on how to resolve this? I have Parallels setup to optimise for documents and I mainly use it for the windows version of office 365 used by my company.