I frequently have applications become unresponsive while they're in the background. That is, I'm not able to switch back to them*, and the Force Quit Applications window shows them as "Not Responding". They never become responsive again no matter how long I wait.

Some features that make this problem unusual:

  • It's not limited to one or two applications. It's happened with MS Office applications, Textedit, BBEdit, Evernote, OpenOffice, Preview, and others.
  • It's not limited to times when the application is doing something intensive. In fact, it usually happens to apps that have been in the background and not doing anything in particular.
  • I've never observed it to happen to web browsers or to music players that are playing music.
  • It doesn't seem to be triggered by other applications doing things that are CPU or memory-intensive.
  • Other applications are not slowing down or hanging when it happens.
  • The non-responding application shows < 1% CPU usage in Activity Monitor.
  • If I force quit the application and restart it, then the problem usually doesn't recur quickly.

Does this suggest any potential causes or troubleshooting steps? I know the usual advice is to either start with a new account or disable all of my other programs and customizations one by one, but I'm hoping that the specific features of this problem might help me proceed in a more targeted way.

System info: Macbook Pro, 2012 model, OS 10.9.4, 8GB RAM, 500GB HDD with 160GB free

* Specifically, what I mean is that I can cmd-tab to the application's icon, but the program in the foreground doesn't change. If I expose one of its windows, I can move the window around, but clicking in it doesn't bring the application to the foreground or affect the contents of the window. Notably, I do not get the beachball / pinwheel pointer when hovering over it, as I do in other cases when an application is stuck.


Here's the system log from an incident when OpenOffice became unresponsive. I discovered it at 8:17. I don't know exactly when it failed, but the last log message and the last revision time on my auto-saved files is 7:46, so I assume it was within 5 minutes of that. Note that the OpenOffice error in the log (appears as soffice) shows up twice, five minutes apart, meaning that the first one wasn't fatal and so I suspect the second wasn't the cause of the hang either.

  • A detailed Console report would help to maybe see what is happening. Use a stuck application name to search your Console data base for your report.
    – Ruskes
    Sep 9, 2014 at 6:05
  • Is that the problem of your Mac OS? Have you ever reinstalled OS for your Mac?
    – GorgeRang
    Sep 9, 2014 at 8:15
  • @Buscar웃 There don't seem to be any log entries related to the stuck applications.
    – octern
    Sep 11, 2014 at 0:45
  • If you would be so kind and publish a log anyway, you might have missed something in it.
    – Ruskes
    Sep 11, 2014 at 0:47
  • I'll do that next time I catch it -- as is so often the case, asking for help with the problem seems to have made it temporarily disappear.
    – octern
    Sep 11, 2014 at 3:42

1 Answer 1



I will work with you on this step by step.

First to eliminate the following:

process plugin-container[1362] caught causing excessive wakeups. EXC_RESOURCE supressed due to audio playback
9/11/14 7:58:33.000 AM kernel[0]: process firefox[1359] caught causing excessive wakeups. Observed wakeups rate (per sec): 163; Maximum permitted wakeups rate (per sec): 150; Observation period: 300 seconds; Task lifetime number of wakeups: 61563

These messages are triggered by a plugin that you're running.

Go to Tools : Add-Ons : Plugins (in Firefox), and one-by-one, for each plugin listed, please do the following:

1) Disable the plugin. 2) Restart Firefox and check if you still see the message.

  • Update and part 2:

Your Preview is generating lots of problems?

Lets start with obvious.

Open Preview:


Open Recent,

Clear Menu

The reason: There seems to be a croup file in your Preview.

  • The culprit appears to be Flash. I have it set to request permission on all sites, and the error reliably appears about 30 seconds after permitting it on one of the pages I use frequently. I will refrain from using it and see if that helps.
    – octern
    Sep 11, 2014 at 18:27
  • Preview hasn't been consistently causing problems, just this morning. I went ahead and cleared the recent files menu.
    – octern
    Sep 11, 2014 at 19:53

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