MacOS – Keyboard shortcut to kill an unresponsive App on Mac OS X

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Today I faced really tight situation on my Mac with Skype (yes, again!) – it went unresponsive, and was not reacting on standard shortcuts, and I wasn't managed to close the app by standard means.

I tried to use the keyboard combo: ⌘ Command + ⌥ Option + Esc simultaneously, but it haven't open the "Force Quit" dialog this time.

I tried to call Activity monitor – but it was not possible either, as the App prevented me switching to something else or to open other applications… no standard means worked, even "Spotlight search" was unresponsive by keyboard shortcut. But I knew it still reacted on the keyboard, as caps-lock was working, plus I managed to power off external display, and the to power it on again via keyboard shortcut.

I'm wondering if is there any fallback for these situations, when an Application is totally unresponsive and prevents me from running other apps? It's the first time the app hanged the whole Mac that heavily, that I was unable to kill it or to open any other application to manage the processes.

Is it normal behavior at all, I was counting on it not possible to hang the whole system on a Mac, and one App can't make it totally unresponsive (OS X El Captain, 10.11.4)?

Update: found such the keyboard shortcut I never used: ⌘ Command + ⌥ Option + ⇧ Shift + Esc held for 3 seconds – forces quit of front-most application… not sure if it would work.

Best Answer

There is a way to access your computer, but only using another computer or device on the same network. That device has to support ssh. OSX has it preinstalled, but if you have an iPhone or iPad you will need to install an app such as Prompt.

You need to allow Remote Login on your mac, from System Preferences. Click the Sharing icon, then check the tickbox for Remote Login.

On the right, there is a list called "Allow Access for". Choose "Only These Users". Then click the + icon and add your user in the list.

(As there was a comment that this is a security risk, you may want to prevent external ssh access in your router, this is beyond the scope of this answer.)

Then if your mac freezes you can remotely connect to it via ssh from the other devices.

From there you could run top to see a list of the processes. You can use the killall command to stop the frozen process by name.

For example

killall Skype

This attempts to Quit Skype.

If that doesn't work, you may have to be less “polite” and add a -9 signal:

killall -9 Skype

If it is severely frozen, the computer may not even respond to the ssh request. In that case I would look at reinstalling your OS or have the hardware checked, which is beyond the scope of this answer.

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