OS X Maintenance – How to Clean Up and Speed Up Your Mac OS X

All computers eventually get clogged up with user files and traces left by different applications. There are also a number of other reasons that can cause the Mac OS X to become slow or unresponsive.

I wanted to share a few things I do for OS X maintenance in order to optimize, clean and speed up my Mac.

Remember, whenever system maintenance is being done there is a chance that something could go horribly wrong! I am only sharing what works for me. Proceed with care, stay safe and always have up to date backups!

Never do anything you’re not sure of!


1. Maintaining the OS X File System via Disk Utility

Disc Utility is a tool with many uses that comes with OS X. You will find it in the Applications/Utilities folder.

Os X maintenance - Disk Utility

There are three functions in Disk Utility I normally use:

  1. Repair Disk
  2. Repair Disk Permissions
  3. Erase Free Space


Repair Disk

The repair disk function is useful for fixing common file system issues. This includes things like corrupt directory structures and files left in unknown state because of crashes, forced restarts or forced application quits. To only identify if you have any issues, run “Verify Disk” first.


Repair Disk Permissions

I try to do this every couple of months. It’s not the end-of-all-problems as some seem to think, but it still pays off to keep your file permissions in check. To only identify issues without making any repairs, run “Verify Disk Permissions”.


Erase Free Space

This is a little feature in disk utility that many people don’t know of. It is meant for rewriting the free space on your hard drive in order to improve security. This is because deleted files don’t actually get properly deleted until the physical part of the disc where they are located is rewritten.

But I use it for different reasons.

What most people don’t know is that this rewriting process of free space can actually increase the available disk space on your drive. I have yet failed to find an exact explanation for why this is. I am not an expert but I’m guessing that over time your hard drive becomes fragmented and more inefficient, and erasing the free space fixes that issue (at least partly).

In any case, the first time I erased free space… 11 GB of more free space appeared on my 750 GB hard drive! Not bad huh? Since then I have erased free space every few months and it always gives me a few extra GB of free space.


2. Obiding The 15% Rule

For good performance, it is recommended to keep at least 15% of free space on your system hard drive at all times.

(If you look carefully at the picture in the previous chapter of this post, you can see that I failed).

According to this test by Macworld, the more free space on your drive, the faster it performs. With the 7200 RPM 1 TB hard drive they tested, the difference in speed was up to 35% (depending on the task) when comparing a 5% full drive to a 97% full drive.

Lesson: Don’t leave clutter or archive material sitting on your work or system disk.

Where does the 15% number come from though? It’s said to be the minimum requirement for your system processes to run properly.

OS X needs free hard drive space for it’s built in defragmentation process and a swap space for managing memory use, among other things.

Individual applications also use the free disk space temporarily. Audio, graphics and video applications can be especially demanding in this respect with temp file sizes reaching several gigabytes sometimes.

If your hard drive becomes too full, it causes your computer to slow down and freeze up. OS X becomes unable to run it’s automatic system maintenance processes properly.

Always having a good amount of free space on your drive also provides good buffer space for when you have to download or handle very large files temporarily.

Are you, like me, finding it hard to keep 15% free? You should, like me, probably think about archiving some of your data. If it’s not being used, it doesn’t belong to your main HD.

Doing a proper cleanup with help of some good software (more on this later) can also help.


3. Cleaning Startup Items

Startup items are applications that launch automatically when your Mac boots up. A lot of software you install tend to sneak their own processes into your startup items. Often times these processes can be absolutely unnecessary.

These unnecessary startup items are eating up your computer’s resources. You should periodically check and clean up your startup items list.

You will find startup items at:
System Preferences -> Users & Groups -> Login Items.

My startup items. Nice and tidy.

My startup items. Nice and tidy.

Note that in order to remove startup items, you need to click the little minus button below the list. The little checkboxes are for hiding startup items (they will still run).

Be careful not to remove stuff you might actually need. If you’re not sure of what something is, I advice you to leave it be and go do some research (Google is your friend there).


4. Getting Rid of Junk: Clean My Mac 3

I’ve been using this brilliant piece of software for a couple of years now and grown extremely fond of it. Clean My Mac 3 by MacPaw is a tool for scanning your computer for all sorts of crap and then getting rid of it.

Clean My Mac 3

Good news.

Getting rid of junk is not only about the files you create or download. Many kids of supporting files are constantly being created by different applications. Ultimately these become useless and can be safely removed.

This not only frees up space on the hard drive, but also makes the system faster and more efficient.

Clean My Mac 3 consists of several cleanup modules, each performing different tasks:

  • Automatic Cleanup (runs all cleanup modules, suggests areas of improvement and let’s you confirm before cleanup)
  • System Cleanup (different cache & log files, broken preferences & login items, universal binaries, development junk, unnecessary language files, etc)
  • Reindex Spotlight
  • Large & Old Files (identifies the space hogs and large files you haven’t used in a while on your drive)
  • Scan Mail attachments & Reindex Mail
  • iPhoto Cleanup (for removing unnecessary photo versions, includes a preview function)
  • iTunes Cleanup (for removing iTunes junk files)
  • Trash Cleanup (knows how to remove locked files too)
  • Uninstaller (for correct removal of applications and all associated files)
  • Extensions Manager
  • Eraser (for secure removal of data)

In addition, there are some very handy maintenance scripts (and more) available.

Clean My Mac 3 just saves me tons of time and frees up resources that I would never otherwise get to on my own. Highly recommended.


5. Dealing With Duplicates and Similars: Gemini 2

MacPaw are one of my favorite software companies. Besides Clean My Mac, they have also created an application called Gemini. Gemini 2 is a godsend for me.

MacPaw Gemini

More good news.

I always end up with lots of duplicate files on my hard drive. Gemini 2 solves this problem in a very sleek way. It searches your hard drive (or the folders you choose) and uses an intelligent process to identify files that are potential duplicates or similars (yes it can even look through your photos and identify ones that are not identical but look similar). It then lets you look at the list of files and make the decisions.

Gemini lets you preview files straight from the interface. It shows exactly where the different files are located and lets you jump to look at them in Finder which is very helpful.

My duplicate problem gets especially bad with iTunes. Over time the iTunes library becomes riddled with differently named versions of the same tracks. What is cool with Gemini 2 is once I have my list of potential duplicates, I can use the preview function and listen to the files straight from Gemini 2. When it comes the time to remove duplicates, Gemini 2 actually launches iTunes to do it properly (without me having to do a thing). Very cool.

MacPaw Gemini

iTunes cleanup with Gemini.


6. Cleaning the Desktop

It’s pretty stupid, but having your desktop cluttered with files actually slows your Mac down. This is because each icon takes up some RAM.

The solution is easy: Clean it up and don’t use the desktop for storing files. Use a different folder. I have created a folder called “Inbox” where most of the temporary file traffic takes place.


7. Software Updates

It’s good to keep your software up to date. I am always quick to install security updates. However, I have grown wary when it comes to upgrading the entire operating system. It’s always a risk if you are relying on your computer to get important work done. When new operating systems are released, it’s quite normal to have all kinds of compatibility issues with 3rd party software and hardware.

Often times these issues are addressed shortly after big updates. But here’s the thing: even a week can be a very long time to wait for an update if you need to get some work done. Also, if you’re using any older hardware/software that isn’t being supported anymore by the devs, you could be screwed. I have had enough first hand experience of these problems in the past. I prefer not to risk it anymore.

So when I have a setup that works well, I try to stick to it for as long as I can. It is important however to make sure that whatever your operating system is, it’s always up to date when it comes to security and performance updates. The same obviously goes for the other software on your computer.


8. Backing Up

Make sure you have a proper backup strategy in place. Here are my recommendations:

  • Automate your backups.
  • Don’t rely on a single backup.
  • Don’t rely on a single location for your backups.
  • Make sure you have access to proper file history (Apple’s Time Machine is great for this).
  • Have the ability to restore your operating system quickly.
  • Have proper archives (archives and backups are different)
  • Verify that your backups are actually working.

My favorite software for backing up:
Backblaze – affordable cloud backups.
Carbon Copy Cloner – maintains a bootable clone of my drive.

For more detailed information on backing up, here are a couple of articles I’ve written before:

7 Deadly Data Backup Mistakes
My Easy Automated Backup Strategy


9. Using the Computer

Other than Os X maintenance, you should also pay attention to how you actually use the computer in order to keep it running optimally. Here are a few tips:

  • Reboot regularly.
  • Properly quit applications you’re not using (don’t just close the windows).
  • Close unnecessary browser tabs (these take up RAM, too).
  • Turn off Bluetooth if you’re not using it.
  • Uninstall applications you’re not using (if you have Clean My Mac, use it’s uninstall function as it removes all traces of the apps that could be left in different locations on your HD).
  • Use Activity Monitor (in Applications/Utilities) to find out about your CPU and RAM hogs.
  • Bypass or remove unused audio plugins in your music projects. They are applications, too.
  • Turn on firewall to help prevent intruders (System Preferences -> Security & Privacy -> Firewall)
  • Make sure cooling works properly and the fans are getting a good airflow (small laptop fans are also prone to get clogged up with dust and debris over time).


Your Mac Maintenance Tips?

Is there something else you are doing that helps keep your Mac running nicely? I would love to hear about it – share your tips in the comments.

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  • sebastian

    Perfect! I’ve been wondering most of these things since making the jump to Mac. Nice post, thanks.

  • Alan

    Nice article. I use Grandperspective to get an overview of files sizes on my disk. Useful for clearing large files you’ve forgotten were there:) http://grandperspectiv.sourceforge.net/

  • Twelve(One)

    This is amazing, thanks a lot for this info. Keep up the great work my man!

  • dhjdhj

    I understand the startup items and 15% empty space. I don’t understand however how any of the other suggestions lead to FASTER performance in terms of running a DAW etc.

  • Legender

    You’re too awesome. I love the majority of your articles.
    This one and the top free plugins article are godsends.

    Thank you for your hard work mate.

  • Like you pointed out, it’s true that freeing up space on the Mac’s hard drive is the most important steps to speed up a slow Mac. Unfortunately, it’s also the hardest and I learned Mac’s waste a lot of space with so many files that we do not need. Your post reminds me of the detox http://WWW.MACBOOKHELPERS.COM performs because it freed up over 6gb on my computer. Thanks for the explanation and tips you always provide; it will help a lot of people.

  • Larry Mkensicki

    I’m using Tweak and Tuneup for my mac, and pretty happy with the results.