The fastest way to open Activity Monitor

Open Spotlight Search by pressing Command + Space, type "Activity Monitor", and press Enter. This is the quickest route on any Mac.

If you prefer using Finder, navigate to Applications > Utilities > Activity Monitor and double-click it. Both methods take you to the same window.

Once Activity Monitor opens, you see a list of running processes, how much CPU and memory each one uses, and other system details. The window updates in real time as programs start and stop.

Key Takeaways

  • Command + Space opens Spotlight Search, where you type "Activity Monitor" and press Enter to launch it instantly.
  • Activity Monitor shows every running process, how much CPU and memory each one uses, and whether a program is responding or frozen.
  • The CPU tab displays processes using processor power right now; the Memory tab shows RAM usage and available memory.
  • You can force-quit a frozen program by selecting it and clicking the stop button, though this may cause unsaved work to be lost.

What each tab in Activity Monitor shows you

The CPU tab displays processes currently using your processor. The "%CPU" column shows what percentage of your processor power each program is using. If one process shows 90% or higher, that program is consuming most of your Mac's processing power and may be causing slowness.

The Memory tab shows how much RAM each process is using. The "Memory" column displays this in megabytes. At the bottom of the window, you see "Memory Pressure" — a graph that turns yellow or red when your Mac is running low on available RAM. Green means your Mac has plenty of memory available.

The Disk tab shows which processes are reading from or writing to your hard drive. High disk activity can slow down your Mac even if CPU and memory usage look normal. The Network tab displays data being sent and received over your internet connection.

How to identify a frozen or unresponsive program

When a program stops responding to clicks or keyboard input, Activity Monitor marks it as "Not Responding" in red text in the Status column. This means the program has crashed or is stuck and will not recover on its own.

Select the frozen program and click the stop button (the circle with an X) in the top-left corner of the Activity Monitor window. A dialog box appears asking whether you want to force the program to quit. Click "Force Quit" to close it immediately. Any unsaved work in that program will be lost.

After force-quitting, you can reopen the program normally. If the same program keeps freezing, try restarting your Mac or checking whether a newer version of that program is available.

Understanding the columns and what they mean

The Process Name column lists the name of each running program or system service. Some names are obvious (Safari, Mail, Finder), while others are background services with technical names you may not recognize.

The PID (Process ID) column shows a unique number assigned to each running process. You rarely need this number unless you are troubleshooting with technical support.

%CPU shows the percentage of your processor that process is using right now. %Memory shows the percentage of your total RAM that process is using. Threads displays how many simultaneous tasks that process is running. Most programs use multiple threads to handle different jobs at once.

Why your Mac might be slow according to Activity Monitor

If your Mac feels slow, open Activity Monitor and click the CPU tab, then click the "%CPU" column header to sort by processor usage. The programs using the most CPU appear at the top. If one program is using 80% or more, that is likely the cause of the slowness.

Switch to the Memory tab and sort by the Memory column the same way. If your Mac has 8 GB of RAM and programs are using 7 GB or more, your Mac is running out of memory. When that happens, your Mac uses disk space as temporary memory, which is much slower. Closing some programs or restarting your Mac frees up memory.

Check the Disk tab if CPU and memory look normal but your Mac still feels sluggish. High disk activity — especially sustained high activity — can slow everything down. If you see a process using the disk heavily, that process may be indexing files, backing up data, or performing another background task that will finish on its own.

Sorting and filtering to find what you need

Click any column header to sort by that column. Click it again to reverse the sort order. Sorting by "%CPU" shows the most demanding programs first. Sorting by "Memory" shows which programs are using the most RAM.

At the bottom of the Activity Monitor window, you see a search box. Type a program name to filter the list and show only processes matching that name. This is useful when you want to see all the background processes related to one application.

By default, Activity Monitor shows all processes. If you want to see only programs you launched yourself (not system services), click the "My Processes" button at the top of the window. This hides background services and makes the list shorter and easier to scan.

When to force-quit versus when to restart

Force-quitting a single frozen program is the right choice when only one application is not responding and the rest of your Mac works normally. Select the program, click the stop button, and click "Force Quit". Your other work continues uninterrupted.

Restart your Mac when multiple programs are frozen, when your Mac is extremely slow even though no single process is using excessive resources, or when a program keeps freezing even after you force-quit it multiple times. A restart clears memory, stops all background processes, and often resolves performance issues that force-quitting alone cannot fix.

To restart, click the Apple menu in the top-left corner, select "Restart", and click "Restart" again to confirm. Save your work first — restarting closes all open programs.

Frequently Asked Questions

Is it safe to force-quit a program?

Force-quitting is safe for the program and your Mac. Any unsaved work in that program will be lost, but it will not damage your Mac or other programs. Use force-quit when a program is frozen and not responding to normal close commands.

What do all these background processes do?

Many processes are system services that keep your Mac running — things like Finder, Spotlight indexing, and security software. You can usually ignore them. If you see an unfamiliar process using a lot of CPU or memory, search for its name online to learn what it does before force-quitting it.

Why does Activity Monitor show processes I did not open?

Your Mac runs many background services automatically, including system updates, cloud syncing, security checks, and indexing. These are normal and necessary. Some third-party programs also run background processes you may not have noticed when you installed them.

Can I close Activity Monitor while programs are running?

Yes. Closing Activity Monitor does not affect any running programs. Activity Monitor is just a tool for viewing what is running — it does not control whether programs stay open. Close it whenever you are done checking your system.

What should Memory Pressure look like on a healthy Mac?

Green memory pressure means your Mac has plenty of RAM available and is running well. Yellow or red pressure means your Mac is using most of its available memory and may feel slow. If pressure stays red, close some programs or restart your Mac to free up memory.