Tips & Advice

The essential guide to cleaning & speeding up your Mac

Sandro Villinger, 20 March 2018

Macs don’t ever slow down, don’t ever crash, and sure as rain don’t ever run out of space. Right? Wrong.

Unfortunately, Macs might be the sports cars of the IT business, but just like any car, they need proper maintenance to keep running. In this guide we’ll walk you through the essentials — and even some great secrets — to clean up invisible clutter and tune up your MacBook, iMac, or Mac Pro beyond its limits. 

If your Mac is running slow, you might be looking at a lot of different symptoms such as applications taking ages to start or your browser feeling sluggish despite a fast internet connection. Other times you’ll hear the fans ramping up to levels that would put your vacuum to shame. Worst case scenario, your Mac slows down to a crawl until it freezes.

Why is my Mac running so slow?

A slow Mac can be caused by a lot of different factors, including:

In this guide, we’ll go through the most common causes of slowdowns and help you fix them.

Technical background

The internals of a Mac are almost identical to modern PCs. And macOS is bound by the same rules that plague Windows: as you install more and more programs or reach the limits of your disk space, you’ll experience drastic slowdowns in your day to day work. In our tests, that slowdown can be even worse than on equivalent Windows machines.

Let’s have a look a look at what happens when we fill up the disk space on a 2016 15” MacBook Pro with touch bar, 2.6 GHz Core i7, 16 GB RAM, AMD Radeon 460 PRO, and a 512 GB SSD.  

Startup time of a Mac with full disk space (lower is better)
50 GB available disk space: 11 seconds
250 MB available disk space: 39 seconds

Launching Outlook 2016 for Mac (lower is better)
50 GB available disk space: 3 seconds
250 MB available disk space: 8 seconds

Converting a 200 MB 4K video file (lower is better)
50 GB available disk space: 9 seconds
250 MB available disk space: 32 seconds

These results partially show how even the fastest machines are bogged down by low disk space. Every click came with a delay or an error message, which is mostly caused by the virtual memory system of macOS and not enough space in the temporary caches of your applications. Without that space, applications won’t work as expected, resulting in either crashes or slowdowns.

But it’s also the additional app or program that runs automatically at startup or in the background that slows things down quite a bit, even on modern Macs.

At any rate, if you’re reading this, chances are your Mac is in some form of peril. This is why we’re here. We’ll start by showing you the essential tips to cleaning up a Mac before we delve into some tips to improve speeds and battery life.

The Basics

Get those updates going

To optimize and boost your Mac’s performance, first things first: make sure that your macOS is up to date. Apple always finds a way to improve performance or to get rid of bottlenecks that plague your Mac. Either way, unless your Mac is hopelessly outdated or not supported anymore, the latest macOS updates tend to make things run smoother.

To check for updates, open the Mac App Store and click on the Updates category. Install updates for everything that you see listed there.


Remove applications you’ve long abandoned

Just like PCs, the more programs you install, the more you have going on in the background. Free yourself from this clutter by going through your list of applications and carefully deciding which ones you need and which ones you don’t.

You’ll find the list by going to your desktop menu bar, clicking on Go and selecting Applications.


To uninstall an app you can either drag it to the Recycle Bin or right-click and select Move to Trash. This isn’t perfect, though. Uninstalling apps typically leaves behind some cache files, settings, or other temporary data which (spoiler alert) you will learn to remove with one of our own tools.

Get some basic disk maintenance going

Every so often your disk needs a regular health check to prevent errors and data loss. If some problems are found, it can instantly fix them. But if it can’t, it is usually a sign that your hard disk is about to give up, which means one thing: backup time!

To perform a scan, click on Go in the menu bar and head over to Utilities. From here, click on Disk Utility. Select your main hard disk and click on First Aid.


Next, you’ll see a summary of issues found. If you see an error, it’s time to launch a repair:


In the example, macOS found corruptions in the file system, which can only be repaired by going into your Mac’s recovery environment and launching First Aid (holding down the Command key + R gets you into recovery mode).

Reset SMC & PRAM once in awhile

SMC? PRAM? Sounds scary, but it isn’t.

All Macs have a System Management Controller (SMC). This is a chip inside your Mac that controls its ports, fans, power button, Wi-Fi, power management, and many other physical parts. By using your Mac and lots of accessories, the SMC could become corrupt.

Meanwhile, the Parameter Random Access Memory (or PRAM) is a small memory chip which contains basic system settings like trackpad sensitivity, date and time, volume, and keyboard backlight. Over time and through many updates, this too can become buggy.

If you’re experiencing strange problems like blank displays, Wi-Fi issues, fans running at full speed, random shutdowns, slowdowns, USB ports not working, and more (the list goes on), then resetting the SMC and PRAM might work well.

How to reset the SMC

Reset SMC: For MacBooks with a non-removable battery
To reset the SMC, you have to shutdown your Mac completely. Now, while it’s off, hold down SHIFT + CONTROL + OPTION on your keyboards (left side), and press the power button. Hold all those keys for 10 seconds (and try not to get a cramp). Release the keys and power on your Mac normally.



Reset SMC: For a MacBook with a removable battery
Shutdown your MacBook, remove the power cord, remove the battery, and hold the power button for at leaast 5 seconds. Then put the battery back, plug your MacBook in, and turn it on. That’s it.

Reset SMC: For your Mac desktop
Shutdown your Mac, remove the power cord, wait for 15-20 seconds, plug it back in, and turn it on. Couldn’t be easier.

How to reset the PRAM 

To reset the PRAM (this applies to all machines), you need to shutdown your Mac and press the power button. Immediately push COMMAND, OPTION, P and R at the same time. Keep these keys pushed until your Mac reboots — then release.

That should fix many strange Mac issues that you couldn’t solve otherwise.

Cleaning up your Mac, top to bottom

Check what’s really occupying your disk

Say you forget all the files you have, and you want to know what’s occupying so many gigabytes of disk space. There’s an easy way to find out. First, click the Mac icon in the top left corner, then click Storage. Wait a bit until the calculation is complete:


In the example, you can see that a massive Photos library, possibly residing in a subfolder that’s been buried, amounts to almost 17 GB. For a more detailed glimpse, go to Manage.

Start with the Recommendations category at the top of the list: Following the advice will help remove iTunes movies and TV shows you’ve watched, empty the trash and sort through files (which takes you to the file manager mentioned above).

Under the first category, Applications, you can see which apps take up the most space (and delete them right away if you don’t need them).


Under Documents, you have an easy view of large files, downloads, and access to  the file browser. The latter shows huge folders and allows you to see what’s hidden where.


Next, you can turn your attention to other files like iBooks to delete books you’ve read or audio books you’ve already listened to.

Oftentimes, iTunes will store massive iPhone backups, which you can delete as they usually take up many gigabytes of space. (But only delete older ones that you’re sure you won’t need!) You’ll find those under iOS files.

Another biggie might be Messages: if you use the app iMessage on your Mac, it stores ALL movies, photos, and even files like PDFs in a hidden folder. In the case below, it grew to 1.27 GB. (And, for real, it took less than 4 weeks!)


If you (like us) are not the most talented musicians, you might want to delete the GarageBand sound library under Music Creation, which can free up 2.3 GB on macOS High Sierra. Last but not least, turn on the iCloud Photo Library which moves your local library to the cloud, saving you another few GBs. Note, though, this only makes real sense for iCloud users.

How to clean cache files on MacOS

You can also do some basic cleaning of application caches, which are files that apps keep around long after they need them. To do this, open Finder and click on Go To Folder in the Go menu. Enter the following: ~/Library/Caches

Now, open up each and every individual folder and empty the content. Do not delete the folders themselves, as this might result in some issues with your apps.


Unfortunately, you have to do this on a regular basis, and this cache is only one area where macOS and your apps store their temporary files. It’s why we built Avast Cleanup Pro which scans your Mac top-to-bottom for these files and gets rid of them automatically for you — across your entire hard disk. Our cleanup application gets rid of all the junk you don’t need on your MacBook, Mac, or iMac.


 Examples of things we clean up:

  • Apple help: Temporary caches from Apple’s help files.
  • Safari user cache: Temporary browsing files from Safari.
  • Location services: Temporarily stored files from the location services of macOS.
  • Spotify: Leftover data from the Spotify app.
  • Photos: Wasteful cache files from the Photos app.
  • Log files: These files are generated on a regular basis by macOS and installed programs when you’re encountering a problem or just to protocol normal operation. For example, macOS logs every crash under /Library/Logs/DiagnosticsReport, which can grow to hundreds of megabytes in size. But when programs crash, the relevant information will be stored in a folder called CrashReporter. These files contain information about your PC, some user information, and, in some cases, a huge amount of data on the crash itself. Unless you’re a developer, this information is useless and can be safely deleted using Avast Cleanup Pro.
  • Trash: The recycle bin of macOS. As many users forget to delete this, our cleanup tool provides a safe way to clear it out in one go.
  • Downloads: As the default location for users’ downloads, this can include long-forgotten and sometimes massive amounts of data the user doesn’t need anymore.
  • Development junk: Programmers will appreciate the fact that Avast Cleanup Pro removes temporary leftover files, such as XCode temp files.
  • External hard disk junk: MacOS also stores temporary files on external disks once they’re connected. We remove these so none of your USB drives are being cluttered with files you don’t need.
  • Duplicate files: Every once in a while, users or programs accidentally copy (duplicate) files. This can happen if you download multiple copies of the same file, duplicate photos or videos to edit and forget about them, or accidentally backup files more than once, just to name a few scenarios. You will be surprised by how many duplicates can be found on even the tidiest Mac.

    Download Cleanup Pro

Speed up your Mac

Slim down your list of startup items

A handful of programs decide they’re important enough to run every time you turn on your Mac, such as Spotify and Skype. This doesn’t just add to your Mac’s startup time, but also impacts overall performance as these program processes keep running in the background all the time.

To prevent them from loading, click on the Apple icon in the top left corner and go to System Preferences. Next, enter the Users & Groups category. Have a look at the Login Items category, as this shows you which apps are being launched every time you boot up your Mac.


In our example, for no good reason Spotify and Chrome put themselves under the login items list, and they pop up windows every time you restart your Mac. If you want to launch apps like Spotify only when you need them,then you should uncheck the applications you don’t need at startup to enjoy a quicker boot, less clutter, and more performance. Just click on an entry and remove it via the minus icon.


Turn off those pesky widgets (Today + Dashboard view)

Essentially, everything that runs in the background, sends out notifications, or checks for updates in any way, shape, or form can have an impact on performance — sometimes noticeable, sometimes negligible.

The macOS widgets seen in the notification area are small apps that run in the background and provide, for example, weather information, reminders, calendars, stock updates, or playback functionality for iTunes. Whatever you don’t need should be turned off.

To turn off macOS widgets, click on the notification icon in the top right corner of your screen, then select Edit. Click on the red minus to remove all the widgets you don’t need in your notification bar.


To turn off widgets, you need to open the Dashboard (e.g. by tapping F12 or the respective key) and get rid of the widget via the red minus icon.


Alternatively, you can turn off Dashboard altogether and save a teeny-tiny bit of extra memory. To do that, go to System Preferences, then to Mission Control, and set Dashboard to Off.

Stop the fancy-pants animations and lipstick

Old Macs with weaker graphic chips and CPUs, especially older than 2010, can be overburdened with the fancy zoom and swooshing animations of macOS. You’ll notice this when minimizing or maximizing windows, moving windows around, or hovering over your application bar. While it won’t make your old Mac run like new, it might be a good idea to turn off any such animations.

To turn off macOS animations, go to System Preferences and open the Accessibility icon. Under Display, check Reduce transparency and Reduce motion.


Next, go back and to the Dock category. Turn off Magnification and Animate opening applications to reduce more of these unnecessary animation effects.

Track down resource-eaters

If your Mac runs slow, hot, loud, or if your battery is running dry too soon, then you might be looking at a program that is constantly thrashing your Mac’s processor, hard disk, network adapters, or graphics processor.

To check what’s going on, you should look at the Activity Monitor to see if there’s a renegade process. To do this, click on Go in the menu bar and then Utilities. Have a look at Activity Monitor on your Mac, and click on % CPU to filter all running processes by the ones that load up your processor the most.


As you can see above, Safari is hogging up 22.5% CPU usage. Looking at the browser, it’s clear to see that the 10 tabs we’ve got open, plus a few downloads, are causing this high usage. In this case, it’s easy to identify the culprit, as it clearly says “Safari Networking.”

But what if a process with a cryptic name pops up and you have NO idea what’s going on? Well, Google is your friend! Usually if you use keywords like “NAMEOFPROCESSS Mac,” then you should find pages and forum entries where the process is being explained. If you don’t need it, quit it by using the X button or uninstall it altogether.

Upgrade RAM & Hard Disk

Now, after all that tuning and tweaking, do you still feel your Mac is sluggish? Unfortunately, as sleek as Macs usually are, upgrading them is not so easy. However, unless you’ve got one of the new 2016/17 unibody MacBook Pros or the thin MacBook, you might be able to expand your device’s memory and hard disk.

When is a RAM upgrade necessary?

If you feel your Mac starts to slow down when you’ve got only 3 or 4 browser tabs open and just a few applications running at the same time, then you might be in the market for an upgrade of your Mac’s main memory. Particularly if you’ve got less than 4 GB. In today’s world of browsers where just a few tabs can easily eat up 1-2 GB of memory, 4 GB of memory is the real minimum. Look at Activity Monitor (mentioned above) to see if you’re hitting the memory limit and what’s eating up all your RAM. A typical upgrade kit (4-8 GB) costs you around $100 and is relatively easy to install (see below for guides).

When is a hard disk upgrade necessary?

Many older Macs still come with mechanical hard disks — spinning platters where bits are stored in individual pits. A read/write head moves across these disks, almost like an old-school LP player, to access the files, programs, and everything your Mac needs to work.

That approach is decades old and is slow. Nowadays, new Solid State Drives (SSDs) are increasingly standard in new computers, and there are many differences between these SSDs and traditional HDDs. If your Mac takes ages to boot, files take a while to open, and if you have to wait forever for any program to load, it might be time for an upgrade. In most scenarios even a lower-end SSD is 10x faster than an old HDD. Some older Macs allow the replacement of the hard disk with something newer.

For both RAM and HDD upgrades, your first step should be to go to and check what kind of upgrades are available for your Mac…


The site includes step-by-step upgrade instructions. If you don’t think you want to touch your hardware, let a skilled technician do the job for you. In both cases, RAM and SSD, you will see and feel a significant benefit.


Common misconceptions are hereby officially busted: Macs do get slower, Macs do get “dirty,” and Macs crash. This guide has shown you where to look for fixes, performance bottlenecks, and unwanted files. But keep in mind, as “trash” piles up over time, you need to repeat some of these steps every once in a while, particularly when it comes to cleaning, maintaining, and checking startup items.

By using the manual method and our cleanup tool you’ll be able to keep your Mac running fresh for many years to come.

Download Cleanup Pro