The Mac's Task Manager: see what's using CPU and memory

Why it happens

On Windows you press Ctrl+Shift+Esc to see every running program. On a Mac that job belongs to Activity Monitor, a free app that comes with macOS. It lists every app and background process, with how hard each one is working.

How to fix it

1. Press Command-Space to open Spotlight, type Activity Monitor and press Return.

   Activity Monitor

2. Prefer the Finder? It lives in Applications, inside the Utilities folder.

   Finder›Applications›Utilities›Activity Monitor

3. Click CPU, then click the % CPU column heading so the busiest item is at the top. Something near 100% for a long time is working very hard.

   Activity Monitor›CPU

4. Click Memory to see what's using RAM. The Memory Pressure graph at the bottom matters most: green is fine, yellow is busy, red means your Mac is short of memory.

   Activity Monitor›Memory

5. Energy shows what drains a laptop battery, and Disk shows what's reading and writing your drive.

6. To end something, select it, click the X button in the toolbar, and choose Quit. If it doesn't close, do it again and choose Force Quit. Leave system items you don't recognise alone.

Still not fixed?

1. Want the quick Ctrl+Alt+Delete version instead? Press Option-Command-Esc to open the Force Quit window for apps that have frozen.

2. Keep Activity Monitor handy: while it's open, Control-click its icon in the Dock, choose Options, then Keep in Dock.

3. If kernel_task is near the top, your Mac is hot and slowing itself down to cool off. Quit the other busy apps and let it rest on a hard surface.

4. If the same app climbs back to the top after you quit it, update that app or restart your Mac. Something stuck often clears after a restart.

5. If a macOS process stays near the top even after a restart and the latest update, contact Apple Support so they can look at it with you.