A Mac rarely gets slow for one reason. Usually it is a combination of too little free disk space, too many things starting up automatically, and one or two apps quietly using far more memory or processor time than they should. The good news is that macOS already includes every tool you need to find and fix each of these.
Work through the steps below in order. The first few take seconds and often solve the problem on their own.
1. Restart your Mac
It sounds too simple, but many Macs go weeks without a real restart. Over time, apps leak memory, background processes get stuck, and temporary files pile up. A restart clears all of that.
Choose Apple menu > Restart. When the dialog appears, untick Reopen windows when logging back in if you want a completely clean start.
2. Quit the apps you are not using
Closing a window does not always quit an app. Any app with a dot under its icon in the Dock is still running. Press Command-Q in each app you do not need, or right-click its Dock icon and choose Quit.
If an app has stopped responding, press Option-Command-Esc to open Force Quit, select it, and click Force Quit.
3. Find what is slowing you down in Activity Monitor
Activity Monitor is the single most useful tool for a slow Mac. Open it from Applications > Utilities, or press Command-Space and type "Activity Monitor".
- CPU tab: click the % CPU column to sort. An app consistently using a large share of CPU while you are not actively using it is a likely culprit. Web browsers, video calls and sync tools are common offenders.
- Memory tab: look at the Memory Pressure graph at the bottom. Green means memory is being used efficiently. Yellow means your Mac may eventually need more memory. Red means it is running short and is relying heavily on the much slower disk. If it is red, quit the apps at the top of the Memory column.
- Energy tab: on a laptop, this shows which apps drain the battery, which often correlates with what makes the fans spin up.
To quit something from Activity Monitor, select it and click the Stop (×) button at the top of the window. Avoid quitting processes you do not recognise; many belong to macOS itself.
4. Stop apps opening at login
Every app that launches when you log in competes for memory and CPU from the moment you start up.
- Choose Apple menu > System Settings.
- Click General, then Login Items & Extensions (called Login Items in older versions).
- Under Open at Login, select anything you do not need straight away and click the – button.
- Under Allow in the Background, switch off background items for apps you no longer use.
You can still open those apps whenever you want; they just will not start automatically. See our full guide to stopping apps opening at startup.
5. Free up disk space
macOS needs free space on the startup disk for virtual memory, caches and updates. When the disk is nearly full, everything slows down, and updates can fail entirely. As a rule of thumb, aim to keep at least 10–20% of the disk free.
Check what is using space in Apple menu > System Settings > General > Storage. The quickest wins are usually:
- Large files and old installers in your Downloads folder.
- Apps you no longer use.
- Old iPhone and iPad backups.
- Media you can stream or download again.
- Emptying the Trash, which does not free space until it is emptied.
Our guide to freeing up storage on a Mac walks through each of these in detail.
6. Update macOS and your apps
Apple regularly fixes performance problems and bugs in macOS updates. Go to Apple menu > System Settings > General > Software Update and install anything available. Update your apps too, either through the App Store or each app's own updater. An old app built for a different processor can be noticeably slower than a current version.
7. Tame your browser
A modern web browser with dozens of tabs can easily use more memory than every other app combined. Close tabs you are not using, or use a bookmark folder or reading list for things you want to come back to.
Remove browser extensions you do not actively use. Each one runs on every page you open. In Safari, go to Safari > Settings > Extensions; in Chrome, open chrome://extensions.
8. Reduce visual effects
On older Macs, transparency and animations take a small but noticeable amount of graphics work. In System Settings > Accessibility > Display, turn on Reduce transparency and Reduce motion. The difference is subtle on Apple silicon Macs but can help on older Intel models.
9. Check iCloud and other sync tools
When iCloud Drive, iCloud Photos, Dropbox, Google Drive or OneDrive are syncing a large number of files, your Mac can feel sluggish for hours. If you have just turned one on or moved a big folder, give it time to finish, ideally while the Mac is plugged in. If a sync tool is constantly busy, check its settings for a folder that is changing more than you expected.
10. Use safe mode to rule out startup software
If your Mac is still slow, start it up in safe mode. Safe mode loads only essential software and performs some checks of your startup disk. If your Mac is noticeably faster in safe mode, something that loads at startup, such as a login item or a system extension, is likely the cause.
- Apple silicon: shut down, press and hold the power button until you see the startup options, select your disk, then hold Shift and click Continue in Safe Mode.
- Intel: restart and immediately press and hold Shift until you see the login window.
Restart normally to leave safe mode.
11. Look out for heat
Macs slow themselves down to protect against overheating. Keep vents clear, avoid using a laptop on a soft surface like a bed or sofa, and check the Energy and CPU tabs in Activity Monitor if the fans run constantly.
12. Know when it is the hardware
If Memory Pressure is regularly in the yellow or red even with only a few apps open, your workload may simply need more memory than your Mac has. Since memory in modern Macs cannot be upgraded, the practical fixes are to run fewer heavy apps at once, use lighter alternatives, or plan for a Mac with more memory next time.
What not to do
- Do not delete files in system folders you do not understand. Some "cleanup" advice online suggests deleting folders inside
/Systemor/Librarythat macOS needs. - Do not install "RAM cleaners". macOS manages memory itself; apps that "free" memory usually just force it to reload data later.
- Do not run Terminal commands you have copied from a forum without understanding what they do.
Frequently asked questions
Why is my Mac so slow all of a sudden?
A sudden slowdown is usually caused by one app using a lot of CPU or memory, a sync tool working through many files, a macOS update finishing in the background, or a nearly full startup disk. Check Activity Monitor and your free storage first.
How much free space does a Mac need to run well?
There is no exact number, but keeping at least 10–20% of your startup disk free gives macOS room for virtual memory, caches and updates. Updates in particular need plenty of free space to install.
Does clearing the cache speed up a Mac?
Clearing caches frees disk space, which helps if your disk is nearly full. It does not make apps faster in itself, and apps will rebuild caches as you use them. Clear caches when you need the space, not as routine maintenance.
Will resetting the NVRAM or SMC make my Mac faster?
Rarely. These resets can fix specific hardware-related issues on Intel Macs, but they are not a general speed fix. Apple silicon Macs handle these automatically on restart.
Want this done for you?
spacerecover scans your Mac for caches, old installers, app leftovers, large files and developer build-up, explains each one in plain words, and clears what you approve in one step. Items go to the Trash first, so you can undo.