How to kill background processes on Mac?

If your Mac is slowing down or acting up, it may be because an application or program that’s running in the background is malfunctioning.

Kill processes using Mac’s Activity Monitor

If a task crashes or is taking up too many resources, you can kill it from the Activity Monitor. Here’s how:

Launch Activity Monitor. You’ll see the tasks that are running according to the percentage of each resource they’re using: CPU, Memory, Energy, Disk, and Network. By default, the tasks that are eating up the most resources will appear at the top of the list.
Identify the heaviest processes or those that you don’t need running. You’ll need to kill those tasks.
To kill a task, select it from the list and click the X icon in the top left of the Activity Monitor window.

This will force the process to quit, freeing up the resources it was using up. If this process is critical to your Mac, it will restart. If it’s an application, it will remain shut down until you reopen it.

Shut down processes using Terminal

You can also force processes to quit from Terminal.

Launch Terminal (Finder > Applications > Utilities).
When Terminal is running, type top and hit Return. This will pull up a list of all your currently running processes. As in the Activity Monitor, this list shows your processes in decreasing order of how much of your resources they’re consuming.
When you find a process that’s using too many resources, locate the PID number to the left of its name.
To kill the process, type kill -9 followed by the PID number and hit Return. This will force the process to quit.

Easily remove startup processes

One common reason for Macs running slowly is that programs are launching automatically at startup. These can be helper apps for programs like iTunes or any variety of other apps. In some cases, they might be applications that are no longer needed.

To review the apps and helpers that are launching on startup:

Launch System Preferences from the Apple menu.
Select the pane Users & Groups.
Click on the padlock and enter your password.
Select your username on the left, and click the Login Items tab.
Deselect the checkbox to the right of each application you no longer need. These apps will no longer launch automatically when you log in.

Keep your Mac running smoothly with CleanMyMac X

CleanMyMac X’s Optimization module helps you keep your Mac running without being burdened by unnecessary background tasks. You can use it to easily disable and remove login items and launch agents. Download the app here.

You can view and disable all launch agents from the Optimization section on the left sidebar. Each item has an Enable or Disable status next to it. Click to switch this status and turn the item on or off.

If you want to remove a login item or launch agent altogether, simply select the item and click Perform. You can’t undo this action, so make sure that you only disable an item if you might want to keep it as a launch agent in the future.

Removing login items and shutting down background processes, will concentrate your Mac’s resources on the apps and processes you’re currently using.