How to clean and optimize your macOS system: manually or automatically using the macOS Clear System Data command

Cleaning a Mac is about removing the right files without touching what matters. We recommend starting with a quick backup and a quick storage review so you know where the weight is. Most slowdowns come from overflow in Downloads, Old Installers, Large Caches and Duplicated Files. You can fix these in under an hour manually, or in a few minutes with automation.

Keeping your Mac in good working order is key to getting as much benefit as possible out of your Apple system. Follow our guide to clear up space on your Mac and optimize it, making it faster and more responsive.

To keep your Mac in peak performance, it’s essential to clean the inside of your Mac. It takes a little time, but it’s worth it!

The first step to optimizing your Mac is to update your software. Install any patches, security updates and application updates. It’s important to accept updates from Apple to maintain the security of your computer and to receive any new features and enhancements. Software updates often streamline applications, which makes your Mac more efficient.

Using terminal commands to clean up macOS offers several advantages:

• Faster and More Efficient: Terminal commands can quickly target and remove specific files, caches, and system clutter that accumulate over time. Unlike third-party apps that may scan everything, terminal commands let you clear only what you need, saving time and system resources.
• No Unwanted Software: Third-party cleanup tools sometimes come with additional bloatware or ads. Using terminal commands avoids this and keeps your system lean.
• No Need for Third-Party Software: You don't have to rely on external apps that might not always be as safe or efficient. Using built-in macOS tools ensures you're working with native commands that are optimized for macOS.
• Advanced Options: Terminal offers a level of control that graphical applications may not provide, such as advanced removal of system files or orphaned files that are not easily accessible through a GUI.

Check for programs that automatically start when you turn on your computer. Delete unused programs or remove them from the start up menu.

To find the items that are opening automatically and running in the background, follow these steps:

Open System Preferences and go to Users & Accounts.

Select the login tab.

Remove any apps you don't want to start automatically when you log in to your computer.

It’s also important to turn off your system completely about once a week. Turning off the computer clears the memory and closes any programs that might be running in the background.

Look at your desktop and remove the shortcuts for any programs and documents that you’re no longer using. Delete the programs and documents or move them to storage. Use Software Update to uninstall unnecessary apps.

To get to Software Update, click the apple icon, then select App Store and update or uninstall programs.

Your downloads folder can get bogged down with a lot of old downloads. Move everything in the folder to storage or delete it if it’s no longer used.

To further optimize your system, check and fix your storage disk:

In Applications, select Utilities > Disk Utility.

Choose your storage drive, then select Verify Disk.

If any errors are returned, select Repair Disk.

If you’re running OS X Sierra, you can also optimize your storage automatically. This feature will also move some of your items to iCloud®. To set up your iCloud account, go to System Preferences, then click iCloud.

It’s a good idea to go through the files on your storage disk and remove anything you no longer want: programs you don’t use, games you don’t play, and files you don’t need to keep. Freeing up space on your storage drive will help the computer respond faster.

If you find that your Mac is running out of storage space, it might be time for an upgrade. If you’re using a hard drive, consider getting a solid state drive (SSD).

Your system can also be optimized by cleaning out the cache your system saves every time you go to a website.

If you're using Safari as your browser, follow these steps:
Open Safari and from the menu, select Safari > Preferences.

Go to the Advanced tab and check the Show develop menu checkbox if it isn't already checked.

Return to the browser menu in Safari, and select Develop > Empty caches.

Be sure to back up your data regularly, as well.

Some programs use more processor and memory resources than others.

Here’s how to find out which apps are using memory resources:

In the Finder app, click Applications > Utilities > Activity Monitor > then click the Memory tab and the CPU tab.
You’ll see the processes listed in order of how much memory they’re using
Decide if you need to use the programs that are using the most resources, or if you can close them.

If you consistently need to use programs that use a lot of memory, consider getting more memory (RAM).

Be sure to empty the trash after you’ve removed apps and other deleted items.

Clean the outside of your Mac and more

Cleaning the outside of your Mac prevents dust and grime from interfering with the keyboard and vents. A grimy keyboard can cause stuck keys, slowing down typing. Dusty vents can cause your system to use unnecessary resources on cooling, which can slow it down. As an added bonus, having a clean computer and desk area gives you a psychological boost.

To clean your computer, turn it off and unplug it. Then, use a damp cloth to clean the accumulated dust from any surfaces, being careful to use appropriate chemicals — especially on your screen or monitor. Spray the cleaner on a cloth to avoid getting moisture in any of the ports. Use compressed air to clean around the keys on the keyboard and in the vents. For MacBooks®, use short bursts of air to clean the vents without harming the fans on the inside.

Take this opportunity to identify and tidy up any cables that are tangled around each other. It will be much easier to swap out peripheral equipment if cables are kept untangled and organized.

Following these tips will help clean up and optimize your Mac so you can work and play quickly.