View Full Version : Macbook fan in overdrive

01-01-2017, 06:23 PM
Hi everyone,

today I installed Firefox browser, ever since my fan is running very fast even when FF is not loaded.
I have attached a screenshot of my activity monitor, can anyone see any reason for this?



01-01-2017, 07:21 PM
Reboot. You have a runaway process, probably from FF.

01-02-2017, 04:48 AM

all is now quiet

01-02-2017, 10:20 AM
OK, Dave, now that I'm back at the MBP and not just on my iPhone, I can now, as they say, "teach you to fish" instead of just giving you a fish. The problem you had was the first item in your Activity Monitor posting, the one in red and taking 299%, "com.Apple.WebKit.WebContent." That process, I believe, renders the internet HTML for your browser so it can be viewed. Apparently Firefox may have a bug or problem where it allows the process to "run away" and take over all of the available CPU cycles. The fact that it was red means that it was no longer responding to the Operating System, including any call to stop running and allow other things to have some time in the CPU. Hence, your fans were running fast because the CPU was heating up from all that (useless) work. If (or when) it happens again, use Activity Monitor to find what is running like that and stop it. You can try to quit the application, but if that doesn't work, you can click on the process in Activity Monitor and then on the "X" icon just above the list and either quit or force quit the process. Normally, once that is done, you get control again and the fans should slow down. However, it's a good practice at that point to reboot because it may be that the runaway process is tied to other processes and that your system will be in an unstable state that rebooting will fix.

Personally, I've seen FF run away several times and now no longer use it. But the WebKit has also been known to take off like that in just about every browser, usually from circular references where an ad on one page refers to an ad on a different URL and that URL refers to another and another and another until it loops back to your page and starts all over again. I use Ghostery to block all of that stuff.

01-02-2017, 11:03 AM
Thanks very much for the detailed explanation.
I have not had a repeat of the incident yet but will keep an eye on it.

all the best


01-02-2017, 03:44 PM
Jke the problems FF is currently having with this makes it an undesirable browser at the moment. And Dave download Ghostery whilst in Safari. Have a read of this from the developers:-


01-02-2017, 03:52 PM
Harry, that's what I meant in Post #2.