What is App Nap on a Mac, and should you turn it off?
What App Nap does to background apps on a Mac, how to see it in Activity Monitor's Energy tab, and when it gets in the way.
What is App Nap?
A power saving feature: apps that are hidden, not playing audio and not doing visible work get their timers and processing slowed until you return to them.
How do I see which apps are napping?
Activity Monitor, Energy tab, App Nap column. Yes means it is napping now.
Should I turn App Nap off?
Only for an app that must keep working hidden, such as a long upload that stalls. Some apps have their own setting; for the rest, keeping the window visible or using caffeinate during the task is simpler.
Common questions
Does App Nap save battery?
Yes. It slows apps you are not using so they draw less power.
Why does my app pause in the background on Mac?
App Nap may be slowing it. Keep the window visible or use caffeinate during the task.