Disable Automatic Termination of Apps in Mac OS X Lion & Mountain Lion
Automatic termination is a feature of OS X Lion and OS X Mountain Lion that comes from the realm of iOS, the idea is that after an app is unused for a period of time and becomes inactive, it will automatically terminate to free up resources for other tasks. With the help of the new auto-save feature, the user should theoretically never notice any of this going on and they can continue on with their work as usual when they need to, letting Mac OS X manage processes and resources for them without quitting apps or manual interaction through Activity Monitor.
For the vast majority of users this is a good thing and most are probably completely unaware of the features existence, but not everyone is thrilled with the prospect of dormant applications being quit without their command and some find it really annoying. If you fall into the second category and want to turn off automatic app termination in OS X, here is how to do it. Don’t worry, we’ll also show you how to turn it back on.
Disable Automatic Termination in Mac OS X
Launch Terminal and enter the following defaults write command:
defaults write -g NSDisableAutomaticTermination -bool yes
Relaunch apps that use auto-termination for changes to take effect.
Re-Enable Automatic App Termination in Mac OS X
You can always reenable the default behavior of OS X and turn auto termination back on:
defaults delete NSDisableAutomaticTermination
Or by reversing “yes” to “no” and running the original command again:
defaults write -g NSDisableAutomaticTermination -bool no
Again, relaunch apps for the changes to take effect and to have auto-terminate enabled again.
This is something that Mac OS X and iOS handles fairly well, and if you’ve never been annoyed by the feature it’s recommended to leave it enabled and let OS X manage tasks itself.
Thanks to qwerty for finding the tip in a StackExchange thread.