Why Is My Mac So Slow? 10 Things to Check
Is your Apple Mac taking ages to start, running slowly, freezing or taking a long time to open applications? A slow Mac can be frustrating, particularly when it used to work perfectly well.
The good news is that a slow Mac doesn’t necessarily mean it’s time to buy a new one. There are several things you can check before spending money on repairs or replacement.
This guide covers ten practical checks for MacBook, MacBook Air, MacBook Pro, iMac and Mac mini computers. We’ll start with simple things you can try yourself and work towards possible software and hardware problems.
Is it my Mac, or just one application?
Sometimes it appears you have a slow Mac when the problem is actually limited to one program. For example, Outlook may take a long time to open, search for messages or respond when you click something. Other programs may continue working normally.
If one application is slow, check whether other programs and websites respond normally. If they do, concentrate on troubleshooting the affected application rather than assuming the whole computer needs repairing.
For Microsoft Outlook and other Office applications, check that the software is up to date. Updates can fix bugs and improve reliability and performance. If you use Microsoft 365, open an Office application and select Help → Check for Updates, where those options are available.
If the problem continues, it may require application-specific troubleshooting. Check the Apple Support Website for specific Apple products.
If several applications are slow, or macOS itself takes a long time to respond, follow the 10 checks to investigate the wider problem.
If the Mac is still slow, continue to the first check.
Using a Windows computer? Windows PCs and Apple Macs work differently. If you have a Windows computer, see our separate guide: Why Is My Windows Computer So Slow?
1. Restart your Mac
It might sound obvious, but restarting your Mac is one of the simplest ways to resolve temporary performance problems.
Leaving a Mac running for long periods can allow background processes and applications to accumulate. Some programs may also stop responding properly.
To restart your Mac:
- Save any work you have open.
- Click the Apple menu in the top-left corner of the screen.
- Select Restart.
- Wait for your Mac to shut down and start again.
A proper restart can clear temporary problems and allow macOS to start fresh.
Once your Mac has restarted, check whether its performance has improved.
2. Check for macOS updates
Apple regularly releases macOS updates that can include security fixes, bug corrections and performance improvements.
If your Mac is running an older version of macOS, installing an available update may help resolve problems.
To check for updates:
- Click the Apple menu.
- Select System Settings.
- Select General.
- Click Software Update.
- If an update is available, follow the instructions to install it.
The wording and location of these options may differ slightly on older versions of macOS. On some older Macs, Software Update is found directly under the Apple menu or in System Preferences.
Important: Not every Mac can run the latest version of macOS. Apple gradually stops providing major operating system upgrades for older models, although security updates may continue for some time.
Before installing a major macOS upgrade, check that your Mac is compatible and that your important files are backed up.
3. Check which applications are using your Mac’s resources
Sometimes a Mac becomes slow because one particular application is using too much processing power or memory.
macOS includes a useful tool called Activity Monitor, which allows you to see what is happening behind the scenes.
To open Activity Monitor:
- Open Finder.
- Select Applications.
- Open the Utilities folder.
- Double-click Activity Monitor.
You can also use Spotlight Search by pressing Command + Space, typing Activity Monitor and pressing Return.
Activity Monitor has several tabs, but two are particularly useful:
CPU
The CPU tab shows which applications and processes are using your Mac’s processing power. If one application is consistently using a very high percentage of the CPU, it may be contributing to the slowdown.
Memory
The Memory tab shows how much memory your Mac is using. Look at the Memory Pressure graph at the bottom of the window.
- Green generally indicates that memory is being managed comfortably.
- Yellow indicates that memory resources are becoming more constrained.
- Red indicates that your Mac may be struggling to manage its available memory.
Don’t close unfamiliar processes simply because they appear near the top of the list. macOS needs many background processes to operate correctly.
If a familiar application is not responding, save your work if possible and close it normally before trying again.
If an app is unresponsive, close it using the Force Quit option
- Click the Apple menu in the top-left corner of the screen.
- Select Force Quit
- Select the non-responsive App from the list and click Force Quit
4. Disable unnecessary applications that open at startup
Some applications are configured to open automatically whenever you start or log in to your Mac.
Over time, these can accumulate and make your Mac take longer to start. They may also continue running in the background and use valuable system resources.
To review these applications:
- Click the Apple menu.
- Open System Settings.
- Select General.
- Select Login Items & Extensions.
- Review the applications listed under Open at Login.
Remove applications that you recognise but don’t need to open automatically.
Be careful not to remove security software, backup applications or anything you don’t recognise without checking what it does first.
You can still open these applications manually whenever you need them.
5. Check how much storage space is available
A Mac with very little free storage space can experience problems, particularly when macOS needs room for temporary files, updates and other background tasks.
To check your available storage:
- Click the Apple menu.
- Select System Settings.
- Select General.
- Click Storage.
Your Mac will show how its storage is being used, including applications, documents, photos and other files.
If your storage is nearly full, consider:
- Removing applications you no longer use.
- Deleting unnecessary downloads.
- Removing large files you no longer need.
- Moving photos and videos to an external drive or into iCloud
- Emptying the Trash after checking its contents.
Be careful when deleting files from system folders. Removing the wrong files can cause problems.
You should also make sure important files are backed up before deleting or moving large amounts of data.
6. Check for unwanted software and malware
Although Macs have built-in security features, they are not completely immune to malware or unwanted software.
Unwanted applications, browser extensions and other software can cause unexpected pop-ups, redirects, poor performance and other problems.
Start by reviewing the applications installed on your Mac.
Open Finder, select Applications and look for programs you don’t recognise or no longer use. Don’t delete something simply because you don’t recognise its name. Check what it does first.
Some applications that claim to “clean up” your Mac storage, actually use memory and storage and have the opposite effect.
Also review your browser extensions and remove anything you don’t need or trust.
macOS includes built-in security technologies such as Gatekeeper and XProtect, which help protect your Mac against malicious software.
If you suspect that your Mac has been infected, use a reputable security product or seek professional advice rather than downloading unfamiliar Mac cleaner or antivirus applications advertised in pop-up messages.
Avoid applications promising to dramatically speed up your Mac with a single click. Some of these programs can create more problems than they solve.
7. Check whether your Mac is overheating
Mac computers can reduce their performance when they become too hot. This is a protective measure designed to prevent damage to internal components.
Overheating can be caused by:
- Blocked ventilation openings.
- Dust accumulating inside the computer.
- Using a MacBook on a bed, cushion or other soft surface.
- Applications placing heavy demands on the processor.
- A cooling fan that isn’t working correctly, where the Mac has one.
Make sure your Mac has room for air to circulate. Use a MacBook on a firm, flat surface rather than a bed or cushion.
If you have an iMac or Mac mini, make sure its ventilation openings are not obstructed.
Listen for unusually loud fan noise, repeated overheating warnings or unexpected shutdowns.
Don’t open your Mac or attempt internal cleaning unless you know how to do it safely. If it becomes excessively hot or repeatedly shuts down, it may need professional attention.
8. Could your Mac need a hardware upgrade?
If you’ve tried the previous checks and your Mac is still slow, its hardware may be the limiting factor.
The age of a Mac alone doesn’t determine its performance. Some older Macs can continue to work well, while others may struggle with newer applications and operating system requirements.
There are several things worth considering.
Available memory (RAM)
Memory is used by macOS and applications while they are running. If your Mac has limited memory and you regularly run several applications at once, it may struggle to keep everything running smoothly.
Many newer Macs have memory integrated into the main processor and cannot have their RAM upgraded after purchase. Some older models have different upgrade options.
Storage drive
Older Macs may use a traditional mechanical hard disk drive (HDD), which is considerably slower than a modern solid-state drive (SSD).
Replacing an older hard drive with an SSD can make a significant difference to startup times and general responsiveness, provided the Mac supports the upgrade.
However, many newer Macs have storage permanently integrated into the computer and cannot have their internal drive replaced easily.
Older Mac models
Some older Macs may no longer support the latest macOS versions. This can affect compatibility with newer applications and security updates.
Before buying a replacement, it is worth finding out whether your existing Mac can be upgraded or repaired economically.
9. Check your browser and open tabs
Sometimes it isn’t the Mac itself that is slow. The problem may be your internet browser.
Safari, Google Chrome and other browsers can use considerable memory and processing power, particularly when you have many tabs open.
Try the following:
- Close browser tabs you no longer need.
- Close and reopen your browser.
- Check whether a particular website is causing the problem.
- Update your browser to the latest version supported by your Mac.
- Review browser extensions and remove those you no longer need.
If only one website is slow, the problem may be with that website or your internet connection rather than your Mac.
For more advice, see our guide to protecting yourself from cyber attacks by updating your web browser regularly.
10. Check for unwanted browser extensions
Browser extensions can add useful features, but some can also cause problems.
Unwanted extensions may display advertising, redirect searches, change your browser’s home page or slow down browsing.
To check your extensions:
Safari
- Open Safari.
- Select Safari from the menu at the top of the screen.
- Select Settings.
- Click Extensions.
- Review the installed extensions and remove anything you don’t recognise or need.
Google Chrome
- Open Chrome.
- Click the three-dot menu.
- Select Extensions.
- Choose Manage Extensions.
- Review the installed extensions and remove anything you don’t recognise or need.
Only install extensions from trusted sources. Be cautious when software installers offer to add browser extensions.
If your browser continues behaving strangely, consider resetting its settings after checking what changes will be made.
Still having problems with a slow Mac?
If your Mac continues to run slowly, freezes, displays error messages or struggles to start, the problem may be more complicated than an ordinary performance issue.
It may involve damaged system files, failing hardware, an application compatibility problem or an ageing computer that is no longer suitable for the work you need it to do.
Before replacing your Mac, it may be worth having it assessed to establish whether the problem can be fixed economically.
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