Kernel_task occuping one core, and writing excessively to SSD

[T'hain Esh Kelch]

Any solutions to such a problem? I can't force quit kernel_task, and it constantly hovers above 100% CPU. But far worse is that it writes 150 MB/sec constantly. My computer has idled a couple of days, and I just came back to the machine making regular hickups (Everything freezes for a few seconds) - Looked up Activity Viewer, and behold, kernel_task had written just over 800TB (!!) data!

Spotlight also appeared to be active in Activity Viewer, so I tried force quitting that, and resetting the index database, to no avail. Rebooted. Shut down, then started, no changes. Gotten so desperate I upgraded from MacOS Sequia 15.7.2 to Tahoe 26.1, and that also didn't make a difference. I set the machine to install, and when I came back an hour later, kernel_task had already written 100GB data to the disk, without me even being logged in!

This is on an M4 Pro mini, with 24GB RAM, and 1TB SSD. Only 50% of the RAM is being used on a fresh boot, swap disk is a 0 bytes after an hour, but kernel_task just keeps going... The weird thing is that it writes ~150MB/sec for ~30 seconds, then pauses completely for ~10 seconds, then repeats.

 

[T'hain Esh Kelch]

Huh, what do you know, after having done this for hours, it just randomly stopped. I wonder if it is because the kernel was updated during the Tahoe upgrade. What I did notice though, was that I at the exact same time got several delayed Reminders popups, and a notification that my Focus was automatically shut off.

I will keep an eye on this for the future, and use this thread to log observations. The rampaging kernel_task has done this before, and I don't know how I fixed it last time, although I have a vague recollection of it being related to Spotlight.