How to speed up a slow Mac


There’s nothing quite like that ‘new Mac’ feeling: a swift startup, with apps that snap open on demand, and plenty of space to store your files. Sadly, though, over time that lightning-fast Mac can start to feel like it's struggling to keep up, so we're here to help you get your Mac's performance back on track.


Using Activity Monitor


Macs have a built-in 'Activity Monitor' app which shows everything that's running, and how much of the Mac's resources each app's using.

mac activity monitor

Open Activity Monitor by clicking Finder > Go > Utilities > Activity Monitor

Across the top of the window you'll see several tabs. They all have useful information, but it's the CPU (central processing unit) and Memory tabs that we're interested in here. 

Use these two tabs to find any apps that are using lots of CPU and/or Memory, then quit them if they're not being used.

Closing unused apps


Having lots of apps running can slow your Mac down, as it's keeping everything open at once. Newer versions of macOS and OS X can close unused apps automatically, but only if the apps themselves are designed to do it.

Click the red Close button in the top-left corner of a window and it'll close (you might have to save the information in it first), but it doesn't close the app completely, just the open window.

Look at the Dock and you'll see indicators beside any apps that are still running. To close an app completely, right-click (or click and hold) on its icon then click Quit on the pop-up menu.

If you can't see an indicator beside the Finder app icon, you might have to turn the setting on. Go to Apple > System Preferences > Dock > Show indicators for open applications and tick the box to turn them back on.

Removing Preference Panes


Preference Panes are small apps that run in the background, often on the menu bar. They usually add extra features to apps, or give you information about the computer and its operating system.

Unfortunately, the danger is that they can sometimes be a source of malware, which can affect your Mac.

Preference Panes get their name because after they're installed they'll show at the bottom of the Mac System Preferences.

To remove one, open System Preferences and right click one of the Preference Pane icons. Click Remove 'AppName' Preference Pane to delete it from your Mac.

Reducing login items


Login items start automatically when you log in to your user account. This can be helpful, making sure your favourite apps are ready for you when the computer starts, but having too many will slow your Mac down.

Free your Mac from opening too many apps by going to System Preferences > Users & Groups > Username > Login Items.

Click an item on the list to highlight it, then click the minus (-) button below the window to remove it. This stops the app from opening the next time you log into your Mac.

Freeing up hard drive space


Running out of storage space on your Mac can really slow it down. You should always try to keep the hard drive under 90% full, because your Mac needs some empty space on the hard drive to work properly.

To find out how much space you have free, go to Apple > About this Mac > Storage.

There are a few things you can do if you're running out of storage space on your Mac:

  • Empty the Trash
  • Move personal files to a USB memory stick, external hard drive or cloud storage
  • Delete unused/unwanted apps

Deleting unwanted apps


Unwanted apps can slow your Mac down by Apps can be removed in one of two ways, depending on how it was installed:

Apps installed from the Mac App Store



Click Launchpad on the Dock (the icon is a silver circle with a rocket on it).


Swipe across to find the app the app you want to delete.


Click and hold on any of the icons for a second or two, and they'll start to wobble.


Click the X beside the app icon, then click Delete on the pop-up window to confirm.

Apps downloaded from a website



Go to Finder > Go > Applications.


Drag the app from the Applications folder to the Trash icon on the Dock.


Type your Password to confirm you want to delete it.


Empty the trash to reclaim the space on your hard drive.

There are some applications you might not be able to remove by following these instructions. These are often anti-virus or security apps, or large media editing suites, and they usually have their own special removal tools in the Applications folder. Double click a removal tool to run it.

You can bring your Mac into a Currys store for a free health check. Find out more here.

If you want to speak to an Expert from Team Knowhow, you can contact us here.

Need some more help?


Expert Support

If you've got an issue with any of your kit, our experts are on-call to help 24/7 - in-store, at home, or over the phone.

More info

Expert Repair

When your kit's fully broken, you need it fixed fast. Our accredited experts will get you back up and running in no time.

More info