I have used System Mechanic Pro for over a decade on many machines as I build computers. I’ve never had a problem with it. I’ve used it on WinXP, WinVista, Win7, Win8.1, Win10. I understand that this is just the System Mechanic giveaway and not the Pro version so maybe that’s why there are so many complaints about it. In addition, I’ve never had an occasion to contact their support so if it is as dismal as others have stated I hope I never have to contact them.