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Why is my MacBook Pro so slow?

If you're saying to yourself, "my Mac is running slow", we're here to help. Your Mac or MacBook Pro can start to run slow for a number of reasons. In this article, we will look into some of the most common reasons why your Mac is running slow and - more importantly - how to fix a slow Mac or MacBook Pro

First off, here's a list of the most common reasons:

  • The startup disk is full
  • Too many applications are running at the same time
  • Outdated software or operating system

Let's look at what you can do to fix each of these issues and get you back up and running in no time.

The startup disk is full: don't forget the 20% rule

As a rule of thumb, it's a good idea to keep at least 20% of your hard disk space free. This will keep your Mac running at a good speed and ensure that apps are not slowing it down when they are trying to access and store data on your hard disk. 

The best way to free up some startup disk space is to regularly clean out your hard disk and optimize your storage. Do this by deleting unused files regularly or use an external storage device or cloud storage to hold files you do not use. This will help optimize storage space and keep your Mac or MacBook Pro performing at its best. 

To do this, use built-in features on your MacBook Pro to run a diagnostic of your hard disk:

  1. Click on the Apple symbol on the top left of your screen
  2. Click 'About This Mac' and select the 'Storage' tab for an overview of how much storage space your hard disk has remaining and how it is used by files, music, videos, and other data 
  3. Click 'Manage' to sort and easily remove unused files and free up valuable disk space

Alternatively, you can use third-party apps to clean up your MacBook Pro's hard disk. Apps such as CCleaner for Mac will help you locate unused and duplicate files and remove them. Plus, it can help remove unwanted internet files and cached files. 

We think that once you run our cleaning software, repeating "my Mac is running slow" to yourself (or anyone that will listen), will be a thing of the past! 

Too many applications are running at the same time

Another common cause of why you're asking yourself "why is my MacBook Pro so slow?" is overloading the central processing unit (CPU) with too many or high CPU-intensive apps running at the same time. Having said that, your Mac should be able to handle multiple apps running simultaneously, so the best way to run a diagnostic and check which apps are causing your Mac to run slowly is to use the built-in 'Activity Monitor'. 

Use your Activity Monitor to find intensive apps

  1. Click 'Finder' then select 'Applications' 
  2. Go to 'Utilities' then select 'Activity Monitor' 
  3. Once open, you will receive a real-time diagnostic of all the apps and processes open and using your CPU
  4. Click on the 'Memory' tab to see real-time memory use
  5. You can stop any app by selecting it from the list and then clicking on the stop icon in the top left 
  6. Then click 'Quit' or 'Force Quit' when an app is being unresponsive or you're not using it

Outdated software or operating system

It is always good practice to use the most current operating system available. Apple releases a new operating system almost annually (currently macOS Big Sur 11.0) and each update provides patches and improvements to the operating system for your Mac. Each new version is faster, more secure, and more reliable, plus will contain additional features as well as the slickest design on offer by Apple.

How to upgrade your operating system

Depending on what version is currently installed on your Mac or MacBook Pro, below are the two options for how to install the latest and greatest operating system:

If you're upgrading from macOS Catalina 10.15 or Mojave 10.14

  1. Click 'System Preferences' 
  2. Go to 'Software Update' to find macOS Big Sur 
  3. Click 'Upgrade Now' and follow the instructions on the screen

Upgrading from an older version of macOS?

  1. Click 'System Preferences' in the dock (or in the top-left Apple drop-down menu)
  2. Click on the 'App Store' icon and follow the instructions on the screen. 

NOTE: If you're running an older version like Mountain Lion 10.8, you will need to upgrade to El Capitan 10.11 first.

Now that you know what the three biggest culprits are and how to fix these issues we hope you never have to say "why is my MacBook Pro so slow?" again. If it does get slower over time just come back to these points. You've got this.

Like we mentioned earlier, it's also a good idea to install a cleaning app such as CCleaner for Mac which will help you locate unused files, duplicate files, and cached files and remove them. Remember your goal is to keep at least 20% of your hard disk space free at all times for your Mac to perform at its optimum.


  • Why is my MacBook Pro being really slow?

    Usually, a MacBook Pro being really slow comes down to space, or a lack of it! To speed your Mac up, try clearing unwanted files and apps from your Mac, quit apps when you’re not using them, and make sure all of your third-party apps are compatible with your Mac.

  • Why is my MacBook Pro so slow and hot?

    Your MacBook Pro could be slow and hot because its startup disk is full, too many apps are open, it has outdated operating system or software, or the fan vent is obstructed and there isn’t sufficient ventilation to cool your MacBook Pro down.

  • Should I worry about my MacBook Pro overheating?

    The short answer is yes. When a MacBook Pro overheats it can automatically shut down and you could lose work or have a task cut short, etc. Other annoying outcomes that are common include the laptop running slowly, freezing up, and misbehaving in general.