Asya Karapetyan
Content marketer, who specializes in Mac how-to guides
December 9, 2021
10 minutes to read

If you check your Mac storage usage, you will find a category called System Data. Sometimes, system storage can take up a huge space on a Mac disk. This article will explain what system data is and how you can reduce system storage on your Mac.

System Data volume in Mac storage panel

The provided guide is written by Apple Certified Support Professionals from Nektony’s team, who knows everything about macOS systems. If you have any questions about the safe cleaning of your Mac storage, you can contact our support specialists. We will be happy to help you.

Contents:

  1. What is system data on a Mac and should you clean it?
  2. How to find system data on your Mac
  3. Why does system data take up so much space?
  4. How to clean up system storage on your Mac.

Tip to safely clean up system storage on a Mac

Most of the files from system storage, like caches, logs, mail downloads, leftovers of already removed applications, and other temporary files, can easily be removed with a special software tool called MacCleaner Pro.

Mac Cleaner Pro automatically finds all types of junk files and safely clears them with a few clicks. You can download a free trial of MacCleaner Pro and see how easy it is to clean up and speed up your Mac with this app.

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Video guide: How to clean up Mac’s system storage

What is system data on a Mac and should you clean it?

Most users think that the System Data category on a Mac includes caches and other temporary files that help the system to work properly. Actually, besides the temporary files, system storage includes other types of files.

System storage includes:

  1. Caches, logs, fonts, plugins, extensions
  2. System and applications temporary files
  3. Time Machine backups
  4. Archives and disk images (.zip, .iso, etc.)
  5. All files from the user’s library
  6. Other hidden files
Note, in macOS Big Sur and earlier versions, the System Data is called Other.

While in macOS Monterey you can see macOS and System Data volumes separately, the Other category includes both these items. In our previous article, you can learn more about Other storage on Mac.

To see your system data volume, do the following:

  1. Go to the Apple menu and select About this Mac.
  2. Switch to the Storage tab.
  3. Here, you will find your storage usage bar chart with system data volume information. Mac storage usage panel showing system data
  4. Click the Manage button.
  5. You will see a new window with the recommendations to free up space on your Mac. Managing Mac disk usage window with system data highlighted

Here, you also will find the Other Data category. However, unlike other types of items in the sidebar, you can’t manage your system storage and can’t see what files are associated with this category.

By default, Apple hides system data because removing some important files can damage the system; however, some of the system storage data is unneeded and can be safely removed. Caches, broken service files, old backups, and temporary files of already removed applications can all be removed. Moreover, it is recommended to periodically clean up your system storage from unneeded files, because a low free disk space can cause your Mac performance to slow down.


How to find system data on a Mac

Most of the files from the system storage category are located in the System and Library folders. By default, Apple keeps these folders hidden to protect them from being accidentally deleted or removed. However, you can get access to them via Finder’s menu.

How to find system files in the Library:

  1. Open Finder.
  2. Press Command+Shift+G.
  3. In the search panel, type ~/Library and press Return. Go to the folder search panel
  4. You will see the Library folder containing many subfolders with applications and system service files. Library folder showing service files

How to easily access the Library folder and system files:

  1. Open Finder.
  2. Go to your Home folder from the sidebar. You can also press Command+Shift+H.
  3. Right-click in the Finder window’s free space and, from the context menu, select Show View Options.
  4. In the window that appears, enable the Show Library Folder option. View options preferences for Finder showing how to unhide Library

Why does system data take up so much space?

You may notice in the storage usage bar that system data is high and takes so much space on your Mac. By default, the average size of a macOS system is 12-16 GB. Therefore, if your system storage (macOS + system data) takes around 40-50 GB, then that’s okay.

If your system data is huge and takes up most space on your Mac, then you most likely have lots of applications whose caches you never cleared. Another possibility is that you have many remaining files of already removed applications. If you delete applications by just dragging and dropping them into the Trash bin, read our article “How to completely uninstall applications on Mac.” In fact, the applications’ leftovers might remain on your Mac and occupy valuable space in your system storage.

If you have cleaned up your system storage by removing caches and other junk but it continues taking up a lot of space, it might be a system error.

Try the following to check and fix this issue:

  1. Reboot your Mac in a Safe mode. For this, hold the Shift key when pressing the Power button.
  2. Go to the Apple menu → About This Mac → Storage, and check your System Data volume. In Safe mode, it should display accurate system usage.
  3. Restart your Mac in a normal mode and check your system storage again. The issue should be fixed.

You can also check how much space your system data is taking on your drive with Disk Space Analyzer from Nektony, which is included in the MacCleaner Pro bundle. Just open Disk Space Analyzer and click to scan your Macintosh HD. The application will scan your hard drive and provide a convenient sunburn diagram of your disk usage. Here, you can navigate through folders; for example, check the Library folder and see what system files are taking the most space. Disk Space Analyzer window showing the volume of application support files


How to clean up system storage on your Mac

You can find and remove all types of items from the System storage manually. Below, we will explain how to manually reduce your system storage. However, if you are new to Mac and don’t clearly understand the macOS file system, we recommend doing this automatically with the help of special software called MacCleaner Pro.

Quick steps to reduce system storage with MacCleaner Pro:

  1. Download and launch MacCleaner Pro.
  2. Go to the Clean up section.
  3. Select the junk files you don’t need.
  4. Click Review and Clean Up and confirm the action.
MacCleaner Pro showing cache files and other junk With additional tools from the MacCleaner Pro bundle, you can also remove support files of already removed applications, extensions, logs, and other unneeded service files.

Manual steps to reduce system storage on Mac

1. Remove caches

Both system caches and application caches are located in the Library folder. To get to the Library and remove cache files, do the following:

  1. Open a Finder window.
  2. Go to the Finder menu, click Go → select Go to Folder.
  3. In the window that appears, type ~/Library/Caches and press Return. Go to Folder search panel showing the Caches folder location
  4. You will see the Caches folder. Remove the subfolders containing cache files of your applications. Library folder showing caches
  5. Go to /Library/Caches folders (without the “~”) and remove unneeded caches from there.

2. Remove service files

Besides caches, there are lots of other service file applications stored on your Mac. Extensions, logs, cookies, plugins: all of them are the files that macOS recognizes as system data. Moreover, some extensions and plugins may negatively affect your system, such as making your Mac run slowly, so you should remove them.

Steps to manually remove applications support files:

  1. Open Finder.
  2. Go to Finder’s menu, select Go → Go to Folder.
  3. Navigate the ~/Library folder.
  4. In Library, check the following folders:

    • ~/Library/Application support
    • ~/Library/Logs
    • ~/Library/Containers
    • /Library/Application support
    • /Library/Logs
    • /Library/Containers
  5. Select and remove all unneeded service files.
Important! Be careful not to remove the subfolders with the name starting with com.apple… This can damage your system.
Library folder showing Application Support folder

Here, you may find the remaining files of already removed applications. Usually, the third-party applications’ support folders have names of the applications or developers.

Instead of manually searching for application support files and leftovers of uninstalled programs, you can use one of the tools from the MacCleaner Pro bundle.

  1. Launch App Cleaner & Uninstaller from MacCleaner Pro.
  2. Switch to the Remaining Files section.
  3. Select all leftovers.
  4. Click Remove and confirm the action.
App Cleaner & Uninstaller showing remaining files of removed applications

You can also use this software tool to reset applications, get rid of their support files, or completely uninstall programs on your Mac.

3. Remove Time Machine backup snapshots

Backing up your Mac with a Time Machine is a great idea. However, despite saving your data on external storage, macOS also creates snapshots of those backups every day and stores them on your Mac startup disk.

By default, these snapshots are only saved if you have enough free space on your disk. Also, the system automatically removes old snapshots when new ones are created. This is great when you have to restore some files, but these items take up significant space on your Mac.

To stop Time Machine from clogging your system storage, you can turn off this feature, which will automatically remove old backup snapshots. Here’s how to do this:

  1. Open System Preferences.
  2. Go to the Time Machine section.
  3. Disable the option Back Up Automatically.
Time Machine section in System Preferences

Also, you can remove old backup snapshots with a Terminal command line.

  1. Open Terminal.
  2. Copy and paste the following command and press Enter.
    tmutil listlocalsnapshotdates
  3. You will see the list of backups on your Mac.
  4. To delete any of the backups, use the following command and press Enter:
    ​​tmutil deletelocalsnapshots ???

The ‘???” should be changed to the name of the backup snapshot file Terminal displayed above.

4. Update macOS

When you download a new macOS update but don’t update your Mac, its installation file takes up space in your system storage. Once you update your Mac, this file gets cleared from your disk.

To update your Mac, do the following:

  1. Open System Preferences.
  2. Go to the Software Update section.
  3. Click to update the system.
macOS software updates window

Podcast: How to clean up your Mac’s system storage

To sum up

Before you start clearing your system storage, check which files are taking up the most space. Caches and applications’ leftovers may take up huge space in your system storage. You can easily analyze what’s taking space on your Mac and safely remove all unneeded system files with MacCleaner Pro.

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