CPU usage is too high with Catalina when macbook-pro connected to an external monitor The same problem was occurring on the High Sierra. I was hoping it will be fixed on Catalina but unfortunately, I didn't.

I use Catalina 10.15.1 on my MacBook Pro and work with an external monitor that is connected with HDMI.

The issue is that, according to Activity Monitor, the kernel_task process consumes more than 600% of CPU even when no tasks are running. The computer becomes totally unusable. I cannot switch between screens and everything freezes.

As a solution, I disconnect the external monitor.

Why didn't Apple fix this issue in the latest Catalina update?

=> Is there an alternative solution for this?

I have followed for the rMBP kernel_task spikes when connecting more than one external monitor [duplicate]

I managed to disable system file protection using csrutil disable, but on Catalina now I am having the following error:

mv: rename X86PlatformShim.kext to X86PlatformShim.kext.disabled: Read-only file system
From your observations it sounds like you have a temperature problem with your MacBook Pro. The system makes the CPU sleep when it detects a temperature problem - this what makes it appear as if kernel_task consumes all the CPU time (it actually doesn't). Usually this is due to either: (a) fan problems, (b) blocked vents or (c) lack of cooling paste. 

I would check these to make sure that fans are working properly, the machine is not full of dust, the vents are free and cooling paste has been applied properly to the CPU.