How to Disable App Nap in OS X and macOS

App Nap is an energy-saving feature that debuted with OS X Mavericks. It puts applications you're currently not using into a "sleep" state, so they don't use system resources such as CPU and battery life until you're ready to focus on them again. These applications immediately wake up when you open their windows.

However, not all users appreciate App Nap's help, fearing that it may prevent background updates or cause slowdowns for some apps. If you're concerned that App Nap is causing problems, it's easy to disable the feature for a single app or shut it down systemwide.

The information in this article pertains to Macs using OS X Mavericks (10.9) through OS X El Capitan (10.11).

How App Nap Works

App Nap suspends an app when the operating system decides it's not performing any useful task. If an app is hidden behind other windows, the operating system checks to see if the app is performing an important task, such as downloading a file or playing music. If the application's function is deemed nonessential, App Nap puts the app into a suspension state. This functionality helps Macs conserve power and battery life, particularly for MacBooks.

While App Nap tries not to interfere with active apps, you may find one of your apps sleeping when it should be working, prolonging tasks that should've already been completed. Sometimes napping apps fail to respond to an input they were supposed to recognize, such as an internal timer, or miss out on background updates. If you find App Nap to be a nuisance, turning it off is a simple process.

When App Nap puts an application to sleep, it's not obvious to the user. To see if an app is sleeping, head to the Activity Monitor and select the Energy tab. In the App Nap column, if there's a Yes next to an application, it's currently napping.

How to Disable App Nap in a Single Application

OS X and macOS enable App Nap by default, but it's easy to turn it off. Note that not all applications are App Nap aware, so you can disable App Nap only in applications that offer this option.

  1. Open a Finder window and select Applications from the left sidebar.

    Mac Finder window with Applications selected
  2. Right-click on the application for which you want to turn off App Nap and select Get Info.

    Get info selected in application right-click menu
  3. Select the triangle next to General to expand the window.

  4. Put a check in the box next to Prevent App Nap.

    Get Info window showing Prevent App Nap option

    If you don't see the Prevent App Nap option, it means this app isn't App Nap-aware and isn't affected by it.

  5. If the app was running, close it and restart it. It will no longer be affected by App Nap.

Disable App Nap SystemWide

If you prefer, disable App Nap for your entire system. You may opt for this if you're not concerned about saving power and battery life and want to allow apps to run background processes at any time.

  1. From the Utilities folder, launch Terminal or type Terminal into Spotlight Search.

  2. In the Terminal window that opens, enter the following command:

    defaults write NSGlobalDomain NSAppSleepD
    Disabling App Nap via a Terminal command
  3. Press Return. Terminal doesn't offer any feedback.

  4. Exit Terminal and relaunch the apps or restart your system.

    To verify that the command worked, go to Activity Monitor and check the App Nap column. All applications should have a No next to them.

Enable App Nap SystemWide

If you change your mind, it's easy to reenable App Nap systemwide.

  1. In Terminal, enter the following command:

    defaults write NSGlobalDomain NSAppSleep
  2. Press Return. App Nap is now active again.