macOS includes a highly aggressive power management feature called “App Nap.” If you have multiple windows open and one window completely covers another, or if you minimize an application to the Dock, macOS assumes you are no longer actively using that hidden application. To save battery life, the operating system instantly throttles the CPU cycles allocated to that hidden app, effectively putting it to sleep.
While this is fantastic for maximizing the battery life of a MacBook Air during a long flight, it is a catastrophic feature for professional workflows. If you are rendering a massive video in Final Cut Pro, compiling code in a terminal window, or downloading a gigantic file in a web browser, the moment you minimize that window to check your email, App Nap kicks in. Your render time will triple, your compile will stall, and your download speed will plummet because the OS is starving the process of CPU cycles. To ensure your background tasks run at maximum velocity regardless of whether they are visible on screen, you must completely disable App Nap.
Disabling App Nap Globally via Terminal
Apple used to include a graphical toggle to disable App Nap for individual applications inside the “Get Info” menu. However, in modern versions of macOS, they removed this checkbox entirely. To kill this power management feature system-wide, you must use the command line.
- Open the Terminal application (press Command + Space, type
Terminal, and hit Enter). - Paste the following command exactly as written and press Enter:
defaults write NSGlobalDomain NSAppSleepDisabled -bool YES - The command will execute silently. To guarantee the changes take effect across all currently running processes, you must completely restart your Mac.
Verifying App Nap is Disabled
Once your Mac reboots, you can verify that the power management throttling has been successfully killed using the Activity Monitor.
- Open the Activity Monitor application (press Command + Space, type
Activity Monitor, and hit Enter). - Click on the Energy tab at the top of the window.
- Look at the column labelled App Nap.
- No matter how many applications you minimize to the Dock, every single entry in this column should permanently say No.
Your Mac will now run at full speed constantly. Background renders, massive file transfers, and automated scripts will execute with maximum CPU priority, even if you hide their windows behind a web browser.