Track Down Runaway Mac Apps


Fried Egg PowerBook
Recently, there’s been a lot of feedback and internal discussion around the topic of Powerbook Fever. Phil’s post about using smcFanControl to cool you Mac down solves part of the problem, but Mac OS X in a Nutshell co-author Chris Stone suggests that overheating is often times the result of a runaway process:

Sounds like it’s hung up on some process. What does ‘top -u’ show? The top line of processes there should show what’s chewing up the CPU and causing the fan to stay on. Rebooting would of course clear that up, but if it starts happening again, check with “top”.

It turns out that a runaway application will not only heat up your laptop, but sometimes even prevent it from sleeping correctly. Those of you that know your way around the command line know where to go from here: just open a terminal window and type top -u.

1047 meanapp 99.3% 0:31.09 1 13 16 176K 560K 468K 26.6M
1049 top 14.6% 0:03.55 1 18 20 1.14M 612K 1.61M 26.9M
213 Terminal 0.6% 8:01.23 14 182 239 5.18M- 19.3M- 28.4M- 246M-
282 Safari 0.5% 2:03:22 12 393 2297 218M 81.9M 277M 833M

If you see an application that’s consuming 99% CPU, such as ‘meanapp’ in the above example, it’s probably the cause of your overheating and laptop sleep issues. Scribble down the process ID of the app (in this case 1047), type “q” to exit top, and force the application to quit by typing kill -9 1047, where 1047 is the troublesome process ID.

If this becomes a regular issue, track down the application that’s consistently causing you problems. Chances are it’s a third party application or driver that could use an upgrade.

12 thoughts on “Track Down Runaway Mac Apps

  1. bjepson says:

    Although a runaway app is likely to require that -9 in there, it’s best to give “kill pid” a shot first, without the -9 (aka -KILL).

    That will send it a trappable signal, so that if the application has some cleanup handler (it may want to close an important file), it can shut down nicely without corrupting whatever data it might be using.

    You can wait a few seconds, and if that didn’t work, send it a -INT signal (as in “kill -INT pid”). Then you can use “kill -KILL pid” as a last resort.

  2. Bre says:

    Hmm, I have a hot mac, but no culprit was found, i’ll keep an eye on this though, thanks!

  3. jason_striegel says:

    Something about giving derelict software a last meal before execution just really burns me. I should caveat this whole post with the fact that I’m often found hard resetting machines instead of waiting for the full shutdown cycle to complete.

  4. marbs says:

    hello mynewbestfriends…

    I am outa my depth on this site — dunno how to open a temrinal window, dunno what kill pid means, etc. — and you may simply roll your eyes and move on, but i figured i’d try to get an answer for a question i’ve had for a while:

    i often hear my computer chattering away, and when i check activity monitor, it is almost always firefox that’s running at 70 percent or 80 percent or whatever. Usually the same sites, but just by surfing, I’ll stumble on new locales that have the same effect.

    So far, the only thing I know to do is kill Firefox and open it again. Is there’s anything else I could do?

    Thanks for taking pity on such an ignorant user…


  5. hi says:


    I’ve noticed that Adobe Flash often uses up a lot of CPU time when you’re browsing certain websites. You might want to try uninstalling some extensions as well.

  6. dancing cobra says:

    Well, to get to the terminal window the mac has to respond. It go so hot I could cook an egg on it (MacBookPro OS X 10.4*). So no clue. Seems to happen everytime I try to open EPS files, it wants to convert them to PDF and doing so for more than 1 file proves too much!!
    Strange isnt it?
    And no terminal window, screen swap or anything possible. No Cmd, Alt, Esc (+/- Shift).

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