My Macair is running extremely. I updated to Sierra Version 10.3.5. Even when there are no apps running CPU usage is around 70%. System processes account for close to 65% and user about 5%.
Kernel_Task shows 200% CPU usage and rest are less than 1 %.
MacBook, macOS High Sierra (10.13.5)
Does this occur for a different user, e.g., Guest?
Does this occur after starting up in Safe Mode?
Consider the possibility of a third party software conflict. EtreCheck can be used to investigate what is installed.
You may have some hardware problems. Maybe the disk and/or battery. You also have cleanmymac which is nothing but trouble and should be uninstalled. That alone might improve things a good bit, if it hasn't already broken your operating system.
CPU usage high even when no apps running
