I have long had issues with both Window Manager and kernel_task taking up seemingly inordinate amounts of resources on my systems going back in the OS release cycle for as long as I can remember, but since I had my MacBook Pro 13" i7 back from the shop with a new SSD, screen, and battery, I did a restore from TM and updated it to 10.13.3 and I actually don't even see either WindowManager nor kernel_task running at all! I will add the this machine has performed better than it ever has, this is likely attributed that to the fact that its puffy batteries were replaced. Who knows what impact those things were having besides warping the chassis.

As I mentioned in another post, on my i7 Mini, suddenly had performance issues while running Sierra for a machine that hitherto been a wonderful machine for the 5 years she's been running without hardly ever a beachball. Honestly, it's been faster than even the newer MacBook Pro 15" 2015 I was issued at work- even though its still the 2012 version. (It was the highest end CPU chipset available - 2.3 GHz - and I maxed out RAM to 16 GB and swapped in a fast SSD with a dual disk kit so it was even at baseline a fantastic machine for the price.)

Unfortunately, as I reported in that other post, it suddenly started suffering from the notorious kernel bloat issue where those familiar processes became the machine's sole purpose as they were generally up top of the proc table as I have seen it on many other troubled Macs in the past. I was downright emotional about it and I received some great suggestions as to how I might resolve it, but since the machine had been upgraded so many times (it literally has not gotten a fresh install since Mountain Lion, yet no performance issues until just now, oddly) I opted for a full install. It was due. I had my installation checklist well defined along with settings (I just need to Automate it next!) so the mini is now running on what is effectively a fresh install of High Sierra. While right off performance is so much better, once I installed Chrome and it synced up with my Google account, crazy things happened and I am now picking its mess off so I can start fresh. Dunno if its an bad extension or what, but its a sloppy mess.

The bigger mystery is that I still see WindowManager now kernel_task near the top of my process table frequently, and though my machine is not limping like it was before, the mystery continues: why are they not even visible on my rebuilt MBP? Is there something hiding those processes when in fact they really are running? It doesn't seem like it as resource usage remains very low. The fact both machines are running the same version of High Sierra I simply don't get how they could be so different. They have practically flip-flopped in their behavior. Even without Chrome my mini gets slammed by the evil duo (WindowManager nor kernel_task) like by Safari. It's a mess!

Signed, Confused in California

  • 1
    Sorry, but is there a question hidden in here somewhere? It reads more like a blog post. If you could edit out the anecdotal aspects to maybe leave the kernel of a question, or even a TL;DR at top or bottom...
    – Tetsujin
    Commented Feb 17, 2018 at 10:30

3 Answers 3


No, there's nothing specifically hiding those processes in Activity Monitor or top.

If you're using Activity Monitor, make sure that on both machines you select the menu View and then "All processes". If you select only to your own processes, you won't be seeing for example kernel_task anymore.

  • I had searched for them before, and I can't imagine why they were not showing, but after typing in "ker" into the filter box on the Activity Monitor there was nothing. Anyway, looking now, kernel_task is of course there (which only makes sense) as I just looked at it hierarchically, so it had better be there! Of course even with a process take 98% CPU, it is meekly using around 6-8% CPU while on the mini it's between 35%-90% at any given time. While it not being there made no sense, the large difference seems very odd, but alas there could be any reason for it.
    – Darf Nader
    Commented Feb 17, 2018 at 16:52
  • By the way, I wasn’t even aware you could filter processes other than with the text filter in the upper right corner. I assumed you could, like bu user and so forth, but never had the need to look for it.
    – Darf Nader
    Commented Feb 18, 2018 at 19:09

Just so there is some answer here that isn’t a divertissement (and thanks for the suggestions, commenters) I found that by turning off ALL of my extensions resolved the issue(s) so whatever data/code that is polluting Chrome is within an extension. Also, reinstalling extensions doesn’t resolve it either, which probably means there is something broken not in the extension install code, but something it writes locally, which I need to take up with the extension creator once I have isolated which one is the offender. I have turned on the two I need most (LastPass and XMarks) and so far so good, but now that I have located a page that loads “funny” consistently with all extensions on, I am about to try each of the extensions one at a time until I find which one breaks that site. When I do, I’ll take it to that specific vendor if I cannot isolate its prefs.

I posted this because this process (as it has many variants) is kind of a core skill in troubleshooting Chrome extension issues, both local and across installations that share a common Google profile) and can used by anyone experiencing Chrome “inckiness” that is traceable to a misbehaving extension. I will post my findings in a comment as the specifics of my actual findings are ancillary to this point, as the meat is in the how. Thanks.


I tried all kinds of things for months to stop a crazy amount of CPU usage from Kernel_task. The solution that finally worked for me was clearing the system/app cache. I moved all the files/folders to another folder and rebooted.


Hope it helps someone else.

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