kernel_task is the macOS kernel itself, shown as a process; it's part of macOS, not malware, and you can't quit it. High CPU from kernel_task usually means macOS is limiting the processor to keep the Mac cool, so close heavy apps, let it cool, and look again when the Mac is idle.
Last reviewed · 4 sources
One Mac, macOS 26.5 (25F71) on Apple silicon, read with ps and codesign on October 29, 2026
| Path | None to show |
|---|---|
| Note | Not a program file: kernel_task is the kernel itself, process ID 0. ps didn't list it; Activity Monitor shows it. |
kernel_task is the macOS kernel's own process. It handles core operating system functions including memory management, process scheduling, hardware I/O, and thermal management. One of its key roles is throttling CPU speed when the Mac's internal temperature sensors detect overheating, which shows up as high CPU usage attributed to kernel_task.
Extremely high CPU usage (200-800%) causing system slowdowns
Fans running at maximum speed even during light tasks
System becoming sluggish and unresponsive during thermal throttling
Persistent high usage after waking from sleep or connecting external displays
Feel your Mac's chassis for excessive heat. If it's very hot, move to a cooler environment, ensure vents aren't blocked, and place the laptop on a hard flat surface rather than soft fabric like a bed or couch.
Open Activity Monitor, sort by CPU, and quit any processes using excessive resources. Video editing, 3D rendering, and multiple Chrome tabs are common culprits that generate heat and trigger kernel_task throttling.
On a Mac with Apple silicon, a restart is all it takes: Apple says the SMC resets automatically. On an Intel Mac the steps depend on whether it has the T2 chip and whether it's a laptop or a desktop, so follow Apple's guide in the sources below.
If kernel_task stays at high CPU with normal temperatures, a faulty temperature sensor may be reporting incorrect readings, so run Apple Diagnostics. On Apple silicon, shut down, press and hold the power button until the startup options appear, then press and hold Command-D. On an Intel Mac, hold D as it starts up.
High kernel_task CPU during intensive workloads is normal thermal management behavior. Be concerned if it stays above 400% CPU while the system is idle and cool to the touch, as this may indicate a faulty temperature sensor, a failing fan, or a hardware issue that needs professional diagnosis.
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Apple says one of kernel_task's jobs is managing CPU temperature: when the processor gets too hot, kernel_task makes the CPU less available to the processes using it hardest, and that shows up as kernel_task's own CPU use. It responds to the heat rather than causing it, and reduces its activity once the temperature drops. Find the app that's working the CPU hard, and the kernel_task number falls with it.
No, and you should not attempt to. kernel_task is the macOS kernel itself — terminating it would crash your entire system immediately. There is no safe way to disable it. If kernel_task is using excessive CPU, the solution is to address the underlying cause (usually heat) rather than the process itself.
No. kernel_task is the macOS kernel (XNU) itself, which Activity Monitor shows as process ID 0. An app can't swap out the kernel, but any program can give itself the name kernel_task, so a second kernel_task, or one that isn't process ID 0, is worth a closer look.
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