> MASTER ACTIVITY MONITOR
Keep track of what’s going on with your Mac’s innards
A ADJUST YOUR VIEW
Activity Monitor can overwhelm with its wealth of data. Use View > Columns to refine its output to what’s important to you. Consolidate the view by, for example, adding Memory and Energy Impact columns to the CPU tab. Also adjust which processes are displayed. You’ll mostly want to display those relevant to your account (via My Processes), although All Processes, Hierarchically is useful if you suspect an issue with the component of a specific app.
B FORCE QUIT APPS
Sometimes apps lock up and get stuck. This is noticeable when you are in an app and the spinning rainbow cursor appears, prior to the app becoming unresponsive. Sometimes, this issue goes away — apps are best left alone for a short while to see if this will happen. If not, a stuck app can be force quit by Ctrl– clicking its Dock icon, holding Option, and selecting Force Quit. In Activity Monitor, stuck apps are colored red and when selected can be force–quit by clicking the quit (cross) button.
C MANAGE BACKGROUND PROCESSES
The macOS App Switcher doesn’t show everything running on your Mac. Apps and utilities run in the background, without a Dock icon. Others run processes that perform specific tasks, such as Photo Library, which checks iCloud to see if Photos needs to download any new snaps. Broadly, avoid force–quitting processes unless they are stuck, but don’t be afraid of using Activity Monitor to quit background apps if you don’t have a need for them to run.
D FIND APP HOGS
Activity Monitor can be an excellent way to check how your Mac’s faring with everything you’re throwing at it. If your Mac’s become generally unresponsive, that might be due to an unruly app or web page hogging CPU or memory resources. By digging into the CPU and Memory tabs in Activity Monitor and arranging relevant columns with largest values at the top, culprits can be quickly weeded out — useful when a web page ends up using a huge amount of your Mac’s entire resources.