What is kernel_task on Mac?
By Junaid, maker of Taskglass · Last reviewed
The core of macOS itself. It also holds busy apps back on purpose to stop your Mac overheating.
kernel_task represents the macOS kernel: the lowest layer of the system, which manages memory, drivers, disks, networking and scheduling for every other process. It always runs and cannot be quit. Apple notes that one of its jobs is temperature control: when the processor gets too hot, kernel_task makes the CPU less available to processes using it heavily, so a big CPU number here is usually a symptom of heat, not the cause of it. Activity Monitor counts 100% per CPU core, so 400% means roughly four cores' worth.
- Category
- macOS system
- Made by
- Apple
- Safe to quit:
- No
Shown in Activity Monitor as kernel_task
Why is kernel_task using so much CPU or memory?
- Your Mac is hot (a warm room, blocked vents, sitting on a bed or lap) and macOS is cooling it down
- Another app was working hard just before and heated up the processor
- Heavy disk, network or external display activity handled by drivers
- Virtual machines or containers (Docker, Parallels, UTM) running in the background
- A faulty third-party driver or system extension
What to do
- 1Give it a few minutes: once the Mac cools, kernel_task backs off on its own
- 2Check which app was using lots of CPU before kernel_task rose, and quit it if you don't need it
- 3Make sure the vents aren't blocked and the Mac sits on a hard, cool surface
- 4Restart your Mac if it stays high while the Mac is cool and idle
- 5If it keeps happening, remove drivers or system extensions you no longer need, or ask Apple Support for a hardware check
Safe to quit? No.
It can't be quit because it is the operating system itself. Its CPU use drops by itself once the Mac cools down.
Typical usage
Rough ranges on Apple Silicon Macs. Yours will vary.
- CPU
- 1–10% when idle; much higher while cooling a hot Mac
- Memory
- Often several GB; this includes memory reserved by the kernel and drivers and is normal
Related guides
Related processes
- WindowServerDraws every window, menu and animation you see on screen, and routes your clicks and keystrokes.
- launchdThe first process macOS starts. It launches and supervises nearly every other background process.
- thermalmonitordWatches your Mac's temperature and helps decide when the system needs to slow down to cool off.
- powerdManages sleep, wake, battery and charging, and tracks apps asking to keep the Mac awake.
Part of the Taskglass Process Library