Macnifying OS X: Learning To Utilize Activity Monitor on Mac

Jackson Chung 10-09-2008

activity monitor macWhenever an application stops responding, there are usually three options to get things back on track again. But first, how would you know if an application has hung? The three cardinal symptoms are the spinning beach ball, increased CPU usage and systemic unresponsiveness. If you’re experiencing any one of these, especially the infamous spinning beach ball of death (SBBOD), you’ve definitely got an application that isn’t working the way it should.


So the first option when faced with a frozen or unresponsive application is to kill it. Not literally, of course! We can try to kill or “terminate” the program. The easiest way to do this is to simply right-click the application in the Dock and select ‘Force Quit’.

Another method is to bring up the “Force Quit Application” menu by pressing ‘Cmd-Option-Esc’ and selecting the application which is non-responsive.

Usually, by forcing an application to quit, we lose any unsaved work. Waiting for the program to resolve itself is a better alternative if you can afford the time. Personally, I’m not quite patient enough. So, it’s a compromise between overworking your CPU and data loss.

Then there is the third method: using Activity Monitor.

Macnifying OS X: Learning To Utilize Activity Monitor on Mac activity monitorOne of the first things I do every time I get my hands on a brand new Mac is to add Activity Monitor to the Dock. Simply because I use it so often, accessibility is crucial. If you didn’t know, Activity Monitor is located in ‘~/Applications/Utilities’. Or you could Spotlight for it.


Activity Monitor is the evil twin brother of Window’s Task Manager. With it, you can see a platter of vital information including all running processes, memory usage, CPU load, hard disk usage & read/write speeds and network activity. Mainly, I use Activity Monitor to deal with unresponsive applications. Notice that I said “deal with” and not “kill/terminate” because you can occasionally actually bring a frozen application back to life just by launching Activity Monitor! It doesn’t work all the time but when it does, you’ll be amazingly thankful.

activity monitor shortcut

If simply running Activity Monitor won’t solve your problem, you could investigate deeper. Under the ‘Process Name’ column is a list of all the applications which are currently running on your computer. The ones which are unresponsive will be labelled red and will be tagged with a clear (‘application not responding’) title. Unfortunately, I can’t provide you with a screenshot because nothing has crashed yet (crosses fingers). To kill a particular hung application, click on it and press ‘Quit Process’ from the menu at the top.

Sometimes, certain frozen applications are more stubborn and are harder to kill, ‘Force Quit’ won’t do the trick. Whenever that happens, try going into the ‘View’ menu and choose ‘Send Signal to Process’. On the window that pops up, choose ‘Hangup’, ‘Interrupt’ or ‘Kill’. I find from experience that choosing ‘Interrupt’ may just bug the application to become responsive again. Just because an application is hung doesn’t mean that it has crashed, so sometimes you won’t need to kill it to restart it again.

activity monitor on mac

Besides using Activity Monitor to force hung applications to quit, it is also useful to provide you with the vital information you need to know about your Mac. CPU load, for instance, is something simple but useful to know at all times. Increased CPU load can make your fans work harder, that makes more noise and your Mac will also run hotter. Most of the time, if you notice an increased CPU when you aren’t performing any CPU intensive tasks, that’s when something fishy is going on.


Activity Monitor’s dock icon is configurable to show you either CPU usage, CPU history, network & memory usage or disk activity but not all at once. If you want access to all this information, I suggest iSlayer’s range of monitoring applications. Personally, I use iStat menus to show my CPU history, network & memory usage and CPU temperature right on my menu bar, which is wicked!

How often has Activity Monitor brought your frozen application back to life? Let me know in the comments. Also, which monitoring application do you use?

Related topics: Restore Data, System Monitor.

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  1. asdffdas
    April 26, 2009 at 10:48 am

    I personally use TOP. Why? Activity Monitor uses up to and including 50% of my CPU. And, yes, before you ask, my computer is fast. Top uses up to 10%. And Terminal can perform MANY functions, while AM can only perform one with many different options.

  2. Aibek
    September 12, 2008 at 4:43 pm

    Jackson, thanks for this great app. You can't even imagine how many times I had to kill the program and lost all the work.

  3. russ
    September 11, 2008 at 11:20 am

    Great post. I use Menu Meters to show CPU usage, Upload/Download speeds, and free/used RAM in the menu bar at the top. Love this and use it all the time!!

    I also use activity monitor to check the processes i'm running, and from time to time I've noticed some fishy processes that I don't think i installed. So activity monitor can be a first check for mac spy/malware. It can also clue you into things that weren't uninstalled when you drag the app to the trash. AppZapper ho!

    • Jackson
      September 12, 2008 at 1:13 am

      Russ! You reminded me about a little point which I forgot to make - Sometimes even after we use AppZapper to remove the components of an application to Trash, we can't completely empty it. This is because sometimes a particular process is still running. So, launch Activity Monitor and search for the process and Quit it, then we're able to empty Trash.