Despite the fact that the Mac operating system is quite stable and responsive, over time you may find your Mac running slow. There may be various reasons for a decline in Mac’s performance. In this article, we will help you to analyze why your Mac is running slow and explain how to improve Mac performance.

Why is my Mac running so slow

The first step to diagnosing a system slowdown is to consider the most common reasons that may cause this.

Here are the top reasons of why Mac computer is running slow:

  • High CPU usage of apps. Using programs for video conversion, backup, 3D rendering, etc., require a large amount of processing power.
  • Insufficient RAM. Some applications require more RAM than is currently available on the system. When the required RAM is not available, the computer constantly saves some of the data from memory to disk.
  • Launching multiple applications simultaneously and having too many applications running in the background.
  • Unnecessary browser tabs left open. Websites with lots of media files and animations can slow down your computer.
  • Lack of free disk space. For normal operation, the system requires at least 20GB of free disk space to store temporary files.
  • Apps that aren’t updated. Using outdated versions of applications may burden the system’s CPU usage.
  • Not restarting regularly. A MacBook may run slowly if it has been running continuously for several weeks without rebooting.
  • The possible use of Mac resources by malware, such as crypto miners.
  • A damaged disk or using an outdated type of disk, for example, using HDD as a system one.

My Mac is running very slow. Can I fix it?

If the reasons for Mac’s system slowdown aren’t addressed, its speed will decrease even more. This may lead to involuntary reboots of the Mac and the loss of user data.
You can download MacCleaner Pro – a special tool to fix a slow Mac quickly or safely. Or follow our guide to manually diagnose why your Mac is so slow and improve its performance.

How to fix a slow Mac

Detect and close memory-consuming apps

If your Mac is running slowly, the problem can be with a particular application. Every application utilizes system resources, so the more apps you have running, the slower your Mac. Moreover, a specific app can require too much CPU and memory.

Follow these steps to identify memory-consuming apps that are causing a system slowdown:

  1. Launch Activity Monitor.
  2. Click View in the Menu Bar and select Windowed Processes.
  3. Click the CPU tab find and select the apps that take up too much CPU usage.
  4. Click the Close (X) button to stop it.
  5. Then switch to the Memory tab.
  6. Find the apps that use too much memory and click the X button to stop them.

macbook pro slow - Quit unused apps


Clear RAM when Mac apps open slowly

If you notice that your Mac is slowing down even when you launch a few apps, then your system needs more free RAM to perform the tasks. Clearing inactive RAM will help to improve your Mac’s performance.

The easiest way to free up RAM is to restart your Mac. Many users do not finish work on their Mac by the end of the day, but just put it into Sleep Mode. In this case, huge temporary files are created. Restarting a Mac allows your system to finish all system processes correctly, flush RAM, and clear temporary files. Also, you should shut down your Mac if you do not plan to use it for several days.

However, restarting Mac to free up RAM is certainly not convenient, since it interrupts your work.

Another option to clear RAM is using the Terminal command line.

  1. Open Terminal.
  2. Paste the command sudo purge and press Enter.
  3. Enter your admin password and again click Enter. Your RAM memory will be cleared.

free memory with terminal

Note, that with MacCleaner Pro you can free up RAM and speed up your Mac with just a few clicks.
  1. Run MacCleaner Pro.
  2. Click on the Performance category or go right to the Speed up Mac section from the sidebar.
  3. Select to Free up RAM and click on Speed up button.
  4. Then you will need just to confirm performing this task.

how to Free up memory mac
MacCleaner Pro also comes with an additional helping tool Memory Cleaner, which can automatically clean up RAM each time your system is out of RAM.

improve slow mac - clean memory


Add RAM to make a Mac run faster

If you need to regularly work with heavy programs on your Mac, you had better increase your RAM; but first, check if it is possible to add more RAM to your computer:

  1. Go to the Apple Menu → About This Mac → Overview. Here you will find the information about your memory.
    about Mac
  2. Switch to the Support tab and click Specifications. It will open the Apple Support webpage with the information about RAM. Find the Memory section and check whether it can be configured on your computer.
    add ram for speed up your mac

*Read the guide on how to install more RAM to your iMac.

add ram for speed up your mac


Update your software

Update the macOS system and all used applications. As a rule, developers create and optimize their applications for the latest version of macOS. If your Mac starts to run very slowly when you launch a specific application, it’s likely the app is not compatible with your system. Check the system requirements for the app, minimum processor speed, minimum RAM, recommended GPU card and so on. Update your apps to make them compatible with your new macOS.

Follow the steps below to check for macOS updates:

  1. Click System Preferences.
  2. Select Software Update.
  3. Click Update Now if a new update is available for your Mac.

update macos

To update apps downloaded from the App Store, do the following:

  1. Open App Store.
  2. Switch to the Updates tab.
  3. Click on Update All.

update apps from app store


Disable startup programs that slow down a Mac computer

Having your favorite programs launch on startup is convenient. However, the more the programs running automatically at login, the slower your Mac startup.

You should disable all login items to make your Mac run faster.

  1. Go to System Preferences → User & Groups → Login Items.
  2. Uncheck and delete apps from the list of Login Items.

disable startup programs

Note, that despite login items, some apps may have extensions – daemons and launch agents, that are hidden or work in the background and run on user login or system startup. You can’t disable them using the System Preferences.

In this case, you can use a special tool from the MacCleaner Pro bundle – App Cleaner & Uninstaller. This app allows you to easily stop all the programs from launching on startup and even remove app extensions.

  1. Launch App Cleaner & Uninstaller and go to the Startup Programs section from the sidebar.
  2. Preview all startup programs on your Mac, especially the Launch agents and Login items sections. Disable or remove unneeded items to stop apps from running automatically when you log in.

check startup items


Check a slow Mac for malware apps

It may happen that your Mac is working slowly because it is being affected by malicious software. Your Mac can receive malware when you download email attachments from unfamiliar senders or apps from untrusted websites.
*Read our previous article How to remove malware from a Mac.

To protect your Mac from malware, first check your security settings:

  1. Select System Preferences and click on Security & Privacy.
  2. Switch to the FileVault tab and turn it on.
    change security settings
  3. Then go to the FireWall and also turn it on.
    remove malware from a Mac

Check hardware when Mac is slow

Another possible reason for a Mac slowdown is damage to or malfunction of the system drive. Use the Disk Utility app to find and solve possible storage issues.

Here is how to check the Mac startup disk for issues:

  1. First, you need to restart your Mac in Recovery mode. Turn your Mac off and restart it by pressing and holding the Command+R keys.
  2. Release the keys as soon as you see a startup window.
  3. Enter your password if needed and click Continue.
  4. Select the Disk Utility section to repair errors on your startup disk in the Utilities window that appears.
  5. Click on the First Aid button and click Run to check your disk for errors.

    macbook slow - check startup disk

  6. If everything is okay, you will see the message that the process is complete, and some errors are fixed. If the operation failed, your disk probably has physical damage and needs to be replaced. Use this information to know how to repair your Mac.

Manage storage to make your Mac run faster

Often a MacBook or iMac runs slowly because there is no free space on the startup disk. If there is a shortage, the system has nowhere to store the temporary files and operate correctly. For stable Mac performance, at least 10% of free space is required. This means that you should clean up Mac storage and recover more free space.

To check how much storage space you have, go to the Apple Menu → About This Mac → Storage.
check Storage on Mac
You can click Manage to see what types of data take the most space and decide what to remove. However, this report does not give a lot of information and only suggests that you will have to free up disk space by deleting files manually, one by one.

We recommend using the MacCleaner PRO, which provides a similar report on disk usage, and immediately provides tools for clearing each category of junk and user files.
manage storage on mac by maccleaner Pro


Clear junk files

Your Mac stores lots of junk files, such as application caches, logs, language resources and so on. Individually these files may occupy only a few kilobytes, but all together they will consume gigabytes.

Manually finding and removing caches and other service files on a Mac is not easy. Here is how to quickly and safely clean up junk files on your Mac with MacCleaner Pro:

  1. Launch MacCleaner Pro.
  2. Click to clean up junk files.
    delete junk files
  3. Select all unneeded types of junk files.
  4. Click on Clean up and confirm the removal.
    speed up slow mac to cleanup junk files

Delete old and large files

You should optimize your disk usage and stop storing bulky content on your Mac hard drive. Recovering some free space will make your Mac run faster. Use the Disk Space Analyzer tool from MacCleaner Pro to analyze your disk space usage, discover large and old files and easily operate them.

  1. Launch Disk Space Analyzer.
    maccleaner pro showing disk space analyzer tool
  2. Scan your Macintosh HD.
    diagram showing mac had drive space uasage
  3. Review the diagram and find large and not used files.
  4. Remove large items or move them to an external storage.

Remove duplicate files

If, after analyzing your disk space usage, you are going to move your bulky data to external storage, we recommend that you first check your storage for duplicate files.

You can find duplicates manually. However, the best way to find and remove duplicate files on a Mac is to use a special tool from MacCleaner Pro – Duplicate File Finder. This tool automatically finds duplicate photos, videos, documents, and any other type of duplicate files. You can even find and clean up similar photos and similar folders.

Here is how to remove duplicates and get more Mac storage:

  1. Launch Duplicate File Finder from MacCleaner Pro.
    find duplicate files by MacCleaner Pro
  2. Add folders and scan them.
  3. Select duplicate files and click to remove them.
    find and remove duplicate files on mac

Uninstall unused apps

You may have many apps that you haven’t used for a long time. You should take a look at all your apps you installed for some earlier tasks, and remove the ones you no longer need. To quickly and completely remove apps from your Mac, use a special tool from MacCleaner Pro – App Cleaner & Uninstaller.

  1. Launch App Cleaner & Uninstaller.
    uninstall apps by MacCleaner Pro
  2. Select unneeded apps.
    delete app on mac
  3. Click to Uninstall them.

So what to do if your Mac is slow?

Now you know all the reasons why your Mac may be running slow and how to optimize its performance. You can fix these issues manually or use MacCleaner Pro, which will keep your Mac clean and free from unneeded apps, extensions, duplicates and malware files.

The MacCleaner Pro software is an all-in-one solution that allows you to safely clean up and speed up your Mac.


MacCleaner tools

Download MacCleaner PRO


This article is based on our expertise in cleaning and optimizing Mac hard drive. We’ve been working 10+ years in developing special disk utilities for making a Mac work smoothly. We regularly explore the latest updates of macOS and update our apps and our articles according to system changes. If you have any questions related to this guide, contact us by email.

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