Why Is My Mac So Slow?

For Mac owners, there are few things as frustrating as poor performance. Apps take ages to open, browsing is sluggish and you’re frequently left waiting while your computer thinks about what to do next. It’s a nightmare. But why is your Mac so slow sometimes? There are countless potential causes, but our team has collected a few that tend to occur more often.

Before we start

It’s always better to prevent Mac slowdown than deal with the consequences. Just download MacKeeper and let it optimize your Mac for you.

These are some of the most common reasons for a slow running Mac:

1. You’re running low on RAM
2. Your hard drive is too full
3. There are too many files on your desktop
4. You have apps storing too many log files and caches
5. Your browser has too many extensions installed
6. You have too many browser tabs open
7. You have malware on your Mac
8. You have lots of startup items
9. Some of your Mac’s hardware is failing
10. Your hard drive or SSD is corrupted
11. Your Mac is overheating
12. Your Mac is too old to support modern software.

How to find out what is slowing down your Mac

How do you even know which one of these factors is slowing down your Mac? There’s no easy answer to that question. It could be any one of them, a combination of two or more, or it could be something else entirely.

Sometimes, there are clues that tell where the problem lies. But other times you have no choice but to try lots of different things, one by one, until you find what’s slowing down your Mac. In most cases, though, it’s usually caused by one of the issues we’ve listed here.

1. You’re running low on RAM

Your Mac’s random access memory (RAM) is where it stores temporary information for quick access. In contrast, your Mac hard drive is used for long-term storage, but it’s much, much slower. Without RAM, everything you do on your Mac would take a lot longer.  

But like your hard drive, your RAM can get full. That can make your Mac run more slowly. Killing background processes can claw back some speed

How to see if your Mac’s RAM is full:

1. Open Activity Monitor from Applications > Utilities > Activity Monitor
2. Go to the Memory tab and look for the Memory Pressure graph at the bottom of the window
3. If the graph is green, you have plenty of RAM left. If it’s yellow, you might be running low. If the graph is red, your RAM space is nearly or completely full.

Simply quitting out of some apps can free up some RAM. But often apps will continue to keep things in RAM, even if they’re not actually running. In such cases, you can use the Activity Monitor to quit those processes too.

But there is an easier way. Many cleaning apps include a Mac memory cleaner, which can clear out files that are hogging up your RAM. These automate memory cleaning, stopping processes you don’t need while leaving the ones you do running.

Of course, you could also add more RAM to your Mac. But with some models, like newer MacBooks and Mac Minis, that’s difficult, if not impossible.

2. Your hard drive is too full

Like any computer, your Mac needs some spare storage space to run properly. When it reaches or gets near to capacity, your Mac can run more slowly, and it will continue to do so until you clear out some data.

How to get an overview of your Mac’s disk space:

1. Click on the Apple icon in the top left of your screen
2. Select About This Mac
3. Now click the Storage tab to see a breakdown of your main disk
4. Hover over the colored sections to see what they are.

One option would be to move some files to the cloud. As a Mac owner, the most convenient solution would be iCloud, which offers 5GB of space for free. 50GB costs $0.99, 200GB is $2.99, and for $9.99 you can get 2TB.  

You could also store files on a USB hard drive, but that requires more effort. It’s also less reliable. External drives can be lost or damaged all too easily.

Often, the best solution is to uninstall apps you don’t need. Also, you should clear out unwanted downloads and duplicate files.  

You can learn more about this in our guide to freeing up disk space.

3. There are too many files on your desktop

There’s no doubt your Mac’s desktop is a convenient place to drop files. But having too many there can cause a significant performance drop. macOS automatically creates previews of files, and if you have a lot of them on your desktop, your Mac will need to load them every time it starts.  

That, of course, can cause your Mac to run slowly. To avoid this from happening, delete or move anything that doesn’t need to be on the desktop. Anything else should be put in a folder or folders. Mac doesn’t create preview icons for folders, so they don’t cause the same issues.

How to turn off icon previews on a Mac:

1. Click on your desktop, then select View > Show View Options from the menu bar. This will open the View Options window for your desktop only
2. Untick Show Icon Preview
3. Now all the icons on your desktop will be shown as generic without file previews.

4. You have apps storing too many log files and caches

When you use browsers and other programs, various files are put into temporary storage areas known as caches. These caches do things like speeding up web page loading when you return to websites. Apps may also create log files to help with troubleshooting.

But these temporary files sometimes remain on your computer even when they’re no longer needed. That can lead to a slow-running Mac. From time to time, it’s a good idea to clear these log files caches to free up disk space, protect your privacy and solve speed issues.   

How to manually clear your app caches on a Mac:

1. To be on the safe side, you should first back up your Mac
2. Next, quit out of any app you have open
3. In Finder, hold the Option key and select Go > Library from the menu bar
4. Navigate to the Caches folder
5. Find the folder that corresponds with the app whose cache you want to clear
6. Delete all the files you find in there and empty your Trash.

In some cases, such as with web browsers, you can clear caches from the settings menu.

You can read more about this in our guide to clearing caches on your Mac.  

5. Your browser has too many extensions installed

Your web browser might be another factor that slows down your Mac. Common culprits in this situation include having too many extensions installed.  

Extensions can be useful in many ways, but they can also slow your Mac down. Removing them can help, and you can do it manually or automatically.

How to remove extensions from Safari:

1. Select Safari > Preferences from Safari’s menu bar
2. Click Extensions  
3. Check the list of available extensions and delete the unnecessary ones by selecting them and clicking Uninstall
4. If you only want to temporarily stop an extension from running, untick it.

You can also update extensions by clicking on the Updates icon in the left-hand sidebar in the App Store.  

How to remove extensions from Chrome for Mac:

1. From Chrome’s menu bar, go to Window > Extensions
2. To delete an extension, find it in the list and click Delete  
3. Click Remove.

If you want to know which Chrome extensions are making your Mac run slowly, take a look in the Chrome task manager. You can find this by going to Window > Task Manager in the menu bar.

Of course, you may want to keep some extensions because they’re useful. MacKeeper’s StopAd, for example, blocks ads when you browse, LastPass stores passwords, and Pocket saves and synchronizes content across devices. Simply removing the ones you don’t want can still get you some speed back.

6. You have too many browser tabs open

If you have a ton of tabs open in your web browser, it can easily slow down your Mac. With most web browsers, each of those tabs is a separate process — almost like you’re running an individual app for each one. The more you have open, the harder your Mac needs to work. These browser tabs can eat up memory before you know it.

How to see which Safari tabs are using up your Mac’s memory:

1. Open the Activity Monitor. You can find this in Applications > Utilities
2. Click Memory
3. Now look for any web addresses under Process Name
4. If any are using up a large amount of memory, close them.

You may also find that some of the web addresses in Activity Monitor are actually extensions, rather than open web pages. If so, follow the previous advice about uninstalling or disabling them.

How to see which Chrome tabs are using your Mac’s memory:

1. In Chrome, select Window > Task Manager from the menu bar.
2. This opens Chrome's own task manager, where you can see how much resources are being used by each tab. Look through the list to see if any are using a lot of RAM or processing time
3. Close any that using up a lot of resources (assuming you don’t need them open, of course)
4. You can also click on processes in the Chrome task manager and then click End Process.

7. You have malware on your Mac

Macs are generally secure, but they can get viruses and other malware. Common sources are malicious websites, file sharing apps, and booby-trapped email attachments.

Sometimes, malware deliberately slows down Macs, but often it’s a side effect of them stealing resources to do other things in the background. They might, for example, use your Mac to send out junk emails to millions of people. Or they might use your Mac’s processing power to mine cryptocurrency.

One way to reduce the chance of a malware infection is to limit what apps can be installed on your Mac. By allowing apps to only be installed from the Mac App Store, you can improve your chances of staying virus-free.

How to limit Mac app installations to the App Store:

1. Open the macOS System Settings
2. Go to Security & Privacy  
3. Click the padlock in the bottom left, then enter your username and password
4. Go to the General tab
5. Under Allow apps downloaded from, click the App Store radio button.

But that’s not all you can or should do to protect your Mac from malware. In addition to being cautious with file downloads, we also advise you to clear caches and run antivirus software to keep your Mac free of malware.

For more information, read our guide to checking for malware on your Mac. Alternatively, give MacKeeper a try. As well as optimization and privacy tools, it offers excellent antivirus scanning and removal.

8. You have lots of startup items

The more your Mac has to load when it starts, the longer it’ll take to get going. So if you find your Mac has accumulated a lot of them, it’s probably a good idea to prune them back a bit.

How to disable startup items on your Mac:

1. Open your Mac’s System Preferences
2. Click on Users and Groups
3. Find your profile and select Login Items
4. Now remove the items that you don’t want to automatically load at startup. Select them and click the minus symbol.

This only accounts for some of the processes that run at startup. There are also likely to be some that run in the background as well. Dealing with those is a slightly different process, though.

Read our guide to changing startup items to learn more.

9. Some of your Mac’s hardware is failing

Computer components don’t last forever. Eventually, they will all break down and stop working. With some components, you might get decades of life out of them. But with others, five years is the average lifespan.

Of course, how long you get depends largely on how often you use your Mac. And when hardware does fail, it can be sudden and obvious or slow and subtle. So if your Mac is running slowly, it could be caused by a component that is still partially working but which is starting to fail.

In many cases, the hard drive or SSD is what goes first. The most effective fix is to replace that part, but that’s often difficult with Macs. But you can get macOS to check your disk for errors.

How to check if your Mac’s hard drive or SSD is okay:

1. Open the Disk Utility from Applications > Utilities
2. Select your Mac’s main drive from the list on the left
3. Now click on the i symbol in the top right
4. If there are any errors on the disk, you may see them here.

If you see a message saying there’s a fatal hardware problem, your hard disk or SSD is damaged beyond repair. But if it only says there are errors on the disk, you can attempt to fix them using Disk Utility.

10. Your hard drive or SSD is corrupted

Occasionally, some of the data on your Mac can get corrupted. This might happen, for example, if your Mac is powered down suddenly — like if it’s unplugged from the mains accidentally while it’s running. That can cause your Mac to slow down if it’s severe enough. Fortunately, macOS’s Disk Utility can often fix disk errors for you.  

How to fix Mac disk drive errors using Disk Utility:

1. In Disk Utility, select your main disk drive
2. Click First Aid
3. Click Run
4. If you see a warning about the scan taking a long time, click Continue.

macOS will verify the data on your Mac, looking for errors. If it finds any, it will try to fix them. In a worst-case scenario, you may need to reinstall macOS to get your Mac back up to speed.  

For more detailed guidance, check out our tutorial on fixing disk errors.  

11. Your Mac is overheating

If they get too warm, Macs will not only spin their internal fans faster — they might also throttle the speed of their components so they generate less heat. This is to prevent parts like the processor from getting too hot and sustaining permanent damage.

Overheating is less of a problem with Mac Pros, which have roomier cases. But iMacs, MacBook Pros, MacBook Airs and Mac Minis are all relatively cramped inside, which makes it harder for them to regulate heat. And there’s an additional problem for MacBooks. As with most portable electronic devices, they use lithium batteries, which can heat up when they’re being used.

Generally, Macs are pretty good at keeping their temperature under control, but it’s worth checking if you think it might be causing your Mac to slow down. macOS doesn’t come with any apps to check the temperature of your components, though, so you’ll need a third-party program. Just search for ‘temperature’ in the App Store to find one.

If your computer is getting too hot, these quick ways to stop your Mac overheating might help.

12. Your Mac is too old to support modern software

Sometimes, the sad truth is your Mac is running slow because it’s just too old. It might have been fine when you bought it, but newer software is generally more demanding. Older  Macs can struggle to keep up.

How to check the age of your Mac:

1. Click the Apple in the top left of your desktop
2. Select About This Mac
3. On the Overview page, you can see some basic information about your Mac, including when it was released.

Using the tips in this guide, you might be able to speed up an old Mac a bit. But eventually, its age will get the better of it. And there’s not much you can do in that situation other than put up with it or buy a new Mac.  

If you’re feeling brave, however, you can speed up an old Mac by replacing its hard drive with an SSD. This will significantly increase loading times, but it’s not easy to do, and you can easily damage your Mac in the process. And with some Macs, such as the latest Mac Minis and MacBooks, the SSDs are soldered in, so they can’t be replaced.

Speed up your Mac with MacKeeper

Assuming your Mac doesn’t have anything physically wrong with it, MacKeeper can often help to speed it up. It has a memory cleaner that can clear out your RAM, it can find and remove junk and duplicate files, and it protects you from malware. These are by far some of the most common reasons for a slow Mac — and MacKeeper can deal with them all and more.  

Give it a try, and see what it can do!

More guides:

• How To Factory Reset MacBook Pro, MacBook Air or iMac
• How to Delete Photos on a Mac
• How to Flush Your Mac’s DNS Cache
• 10 Effective Ways to Clean Up Your Mac
• How to Fix "Your Computer Restarted Because of a Problem"