How to Clear System Storage on Mac: A Comprehensive Guide

Macs are known for their user-friendly interface and robust performance, but even these machines can become sluggish and inefficient over time due to accumulated system storage. System storage, often a mysterious category in your Mac’s storage overview, can hog valuable space, impacting your Mac’s speed and overall performance. This comprehensive guide will walk you through a detailed process of identifying, understanding, and effectively clearing system storage on your Mac, reclaiming valuable space and restoring optimal performance. We’ll cover everything from the basics to advanced techniques, ensuring you have the knowledge and tools to keep your Mac running smoothly.

Understanding System Storage on Mac

Before diving into the solutions, it’s crucial to understand what constitutes system storage on a Mac. Unlike categories like documents, applications, or photos, system storage is a catch-all term for files that macOS deems essential for its operation. This includes:

* **macOS System Files:** These are the core files that run your operating system. While you shouldn’t directly tamper with these, understanding they are part of the system storage is important.
* **Temporary Files:** macOS and applications create temporary files for various processes. Ideally, these should be deleted automatically, but sometimes they linger.
* **Caches:** Caches are used to store frequently accessed data, allowing for faster loading times. However, over time, caches can grow significantly and take up considerable space.
* **Logs:** System and application logs record events and errors. These are helpful for troubleshooting but can accumulate and contribute to system storage bloat.
* **Disk Images (.dmg files):** Installation files for applications that are often forgotten after installation.
* **Archives and Backups:** Local Time Machine snapshots, older iOS backups, and other archive files.
* **Virtual Machine Files:** If you use virtualization software like Parallels or VMware, the virtual machines can consume a lot of space within system storage.
* **Fonts, Dictionaries, and Language Resources:** Additional fonts, dictionaries for different languages, and other localization resources.
* **Miscellaneous Files:** Anything that macOS can’t easily categorize often ends up in system storage. This can include orphaned files, application support files, and other miscellaneous data.

To view your Mac’s storage breakdown:

1. Click the **Apple menu** () in the top-left corner of your screen.
2. Select **About This Mac**.
3. Click the **Storage** tab.
4. You’ll see a color-coded bar graph representing the different categories of storage usage, including System Storage (often represented as dark gray).

Now that we understand what system storage entails, let’s explore the methods for clearing it.

Method 1: Using macOS Storage Management Tools

macOS comes with built-in tools designed to help you manage your storage effectively. These tools provide recommendations and options for optimizing your storage:

1. **Access Storage Management:**
* Follow steps 1-3 above to get to the Storage tab.
* Click the **Manage…** button.

2. **Review Recommendations:**
* The Storage Management window will present several recommendations. Let’s examine each one:

* **Store in iCloud:** This option allows you to move files, photos, and messages to iCloud to free up space on your Mac. When storage is needed, files will be downloaded on demand. Consider the privacy implications and whether you want your data stored on Apple’s servers. To enable:
* Click **Store in iCloud**.
* Choose to store **Desktop & Documents** and/or **Photos** in iCloud.
* Click **Turn On**.

* **Optimize Storage:** This feature automatically removes watched movies and TV shows from Apple TV after you’ve finished watching them, and it prevents email attachments from taking up unnecessary space. Enable this to automatically clean up some unnecessary files.
* Click **Optimize Storage**.
* Choose to automatically remove watched movies and TV shows and/or download only recent attachments.
* Click **Turn On**.

* **Empty Trash Automatically:** This option automatically deletes items that have been in the Trash for more than 30 days. This is a simple way to ensure the Trash doesn’t consume excessive space.
* Click **Empty Trash Automatically**.
* Click **Turn On**.

3. **Review Files:**
* In the left sidebar of the Storage Management window, you’ll see categories like **Applications**, **Documents**, **iCloud Drive**, **Mail**, **Messages**, **Music Creation**, **Photos**, and **Trash**. Click on each one to review the files within them.

* **Applications:** Uninstall applications you no longer use. Large applications can take up significant space.

* **Documents:** Identify large files you don’t need or can move to external storage. Consider archiving older documents.

* **iCloud Drive:** Manage your files stored in iCloud Drive. You can delete files or move them to other storage locations if you no longer need them in iCloud.

* **Mail:** Review and delete large attachments or emails you no longer need. Consider archiving older emails to a separate storage location.

* **Messages:** Delete old conversations, particularly those with large attachments like photos and videos.

* **Music Creation:** If you use music production software like GarageBand or Logic Pro, delete unused loops, samples, and project files.

* **Photos:** Use iCloud Photo Library to store photos in the cloud and optimize storage on your Mac. Delete unwanted photos and videos.

* **Trash:** Empty the Trash to permanently delete files that have been moved there. Remember the ‘Empty Trash Automatically’ option discussed previously.

Method 2: Manually Deleting Temporary Files and Caches

macOS’s storage management tools offer some cleanup capabilities, but sometimes you need to delve deeper and manually remove temporary files and caches. Be cautious when doing this, as deleting essential files can cause problems. Only delete files from locations specified below.

1. **Clear User Cache Files:**
* Open **Finder**.
* Click **Go** in the menu bar and select **Go to Folder…** (or press **Shift-Command-G**).
* Enter `~/Library/Caches/` and press **Go**.
* This folder contains cache files for various applications. You can delete the contents of folders within this directory (but not the folders themselves). For example, you can delete the contents of the `com.apple.Safari` folder to clear Safari’s cache.
* **Important:** Do not delete the entire `Caches` folder itself. Delete only the *contents* of the subfolders within the `Caches` folder.
* Empty the Trash.

2. **Clear System Cache Files (Use with Caution):**
* Repeat steps 1-3 above, but this time enter `/Library/Caches/` (note the absence of the tilde `~`).
* This folder contains system-level cache files. Again, you can delete the *contents* of the subfolders within this directory, but not the folders themselves. Exercise extreme caution when deleting files from this location, as deleting essential system caches can cause system instability. Only delete files if you are absolutely sure they are safe to remove. If in doubt, leave them alone.
* Empty the Trash.

3. **Clear Temporary Files:**
* Repeat steps 1-3 above, but this time enter `~/Library/TemporaryItems/`.
* Delete the contents of this folder. This folder contains temporary files created by applications. These files are generally safe to delete.
* Empty the Trash.

4. **Clear System Temporary Files (Use with Extreme Caution):**
* Repeat steps 1-3 above, but this time enter `/tmp`. This directory holds temporary files for the system.
* The files in `/tmp` are usually automatically deleted upon a system restart, but in some cases files may remain. This step is not recommended unless you have a good understanding of the files that might be located here, and you have a specific reason for deleting them. Incorrectly deleting files in `/tmp` could cause application instability.
* Empty the Trash.

**Important Note:** After deleting cache files, it’s a good idea to restart your Mac to ensure that the changes take effect and to allow macOS to rebuild any necessary caches.

Method 3: Removing Language Files

macOS comes with support for a wide range of languages. If you only use a few languages, you can remove the unused language files to free up space. This process is typically safe, but it’s always a good idea to back up your Mac before making any significant changes.

**Using Monolingual (Third-Party Tool):**

While macOS doesn’t offer a built-in tool for removing language files, you can use a third-party utility like Monolingual. This is a free and open-source application specifically designed for removing unnecessary language resources.

1. **Download and Install Monolingual:**
* Download Monolingual from a reputable source (search for “Monolingual macOS”).
* Open the downloaded DMG file and drag the Monolingual application to your Applications folder.

2. **Launch Monolingual:**
* Open Monolingual from your Applications folder.
* You may be prompted to enter your administrator password.

3. **Select Languages to Remove:**
* Monolingual will display a list of installed languages. Select the languages you want to remove. Be careful not to remove languages you might need in the future.
* **Important:** Leave English selected, as macOS requires it. You may also want to keep languages you frequently encounter in documents or websites.

4. **Run Monolingual:**
* Click the **Remove** button.
* Monolingual will begin removing the selected language files. This process may take some time.

5. **Restart Your Mac:**
* After Monolingual has finished, restart your Mac to complete the process.

**Caution:** While Monolingual is generally safe, it’s essential to download it from a trusted source to avoid malware. Always back up your Mac before using any third-party utility that modifies system files.

Method 4: Removing Old iOS Backups

If you back up your iPhone or iPad to your Mac, these backups can take up significant space. Over time, you may accumulate multiple backups, some of which are no longer needed. Deleting old iOS backups can free up considerable system storage space.

1. **Open Finder.**
2. Click **Go** in the menu bar and select **Go to Folder…** (or press **Shift-Command-G**).
3. Enter `~/Library/Application Support/MobileSync/Backup/` and press **Go**.
4. This folder contains your iOS backups. Each folder inside represents a separate backup.
5. Identify the old or unnecessary backups. You can usually tell by the date of the folder. It’s a good practice to keep the most recent backup in case you need to restore your device.
6. Drag the folders corresponding to the backups you want to delete to the Trash.
7. Empty the Trash.

**Alternative Method using iTunes/Finder:**

With the introduction of macOS Catalina, iTunes has been replaced by Finder for managing iOS devices. The process for deleting backups remains similar:

* **macOS Mojave and Earlier (iTunes):**
1. Open iTunes.
2. Go to **iTunes > Preferences**.
3. Click the **Devices** tab.
4. You’ll see a list of device backups. Select the backup you want to delete and click **Delete Backup**.

* **macOS Catalina and Later (Finder):**
1. Open Finder.
2. Click on your iPhone or iPad in the Finder sidebar (under Locations).
3. Click **Manage Backups…**
4. You’ll see a list of device backups. Right-click (or Control-click) the backup you want to delete and select **Delete**.

Method 5: Removing Disk Images (.dmg Files)

Disk images (.dmg files) are commonly used to install applications on macOS. After installing an application from a DMG file, the DMG file itself is no longer needed and can be safely deleted. Many users forget to delete these files, and they can accumulate over time, taking up valuable storage space.

1. **Open Finder.**
2. Search for “.dmg” in Finder. You can do this by typing “.dmg” in the search bar in the upper-right corner of the Finder window.
3. Finder will display a list of all DMG files on your Mac.
4. Review the list and identify any DMG files that you no longer need.
5. Drag the unnecessary DMG files to the Trash.
6. Empty the Trash.

Method 6: Removing Virtual Machine Files (If Applicable)

If you use virtualization software like Parallels Desktop, VMware Fusion, or VirtualBox, the virtual machines can consume a significant amount of disk space. These files often reside within the “System Storage” category. If you no longer need a virtual machine, deleting it can free up a substantial amount of space.

1. **Identify Virtual Machines:**

* **Parallels Desktop:** Open Parallels Desktop. Your virtual machines will be listed in the Control Center.
* **VMware Fusion:** Open VMware Fusion. Your virtual machines will be listed in the Virtual Machine Library.
* **VirtualBox:** Open VirtualBox. Your virtual machines will be listed in the VirtualBox Manager.

2. **Delete Unnecessary Virtual Machines:**

* **Parallels Desktop:** Right-click (or Control-click) the virtual machine you want to delete and select **Remove…**. Choose whether to move the virtual machine to the Trash or delete it permanently.
* **VMware Fusion:** Right-click (or Control-click) the virtual machine you want to delete and select **Move to Trash**.
* **VirtualBox:** Right-click (or Control-click) the virtual machine you want to delete and select **Remove…**. Choose whether to keep the virtual disk files or delete them along with the virtual machine.
3. **Empty the Trash.**

**Important Considerations:**

* Deleting a virtual machine will permanently erase all data stored within that virtual machine. Make sure you have backed up any important data before deleting the virtual machine.
* Consider archiving older virtual machines to an external hard drive if you think you might need them in the future but don’t want them taking up space on your Mac’s internal storage.

Method 7: Analyzing Storage with Third-Party Tools

Sometimes, it can be challenging to pinpoint exactly what’s consuming the most space within system storage. Third-party storage analyzer tools can provide a more detailed breakdown of your storage usage, helping you identify large and unnecessary files.

Some popular storage analyzer tools for macOS include:

* **DaisyDisk:** A visually appealing tool that scans your disks and presents a map of your files and folders, making it easy to identify large space hogs.
* **Disk Drill:** Primarily a data recovery tool, Disk Drill also includes a disk space analyzer that can help you identify large files and folders.
* **CleanMyMac X:** A comprehensive Mac cleaning and optimization tool that includes a storage analyzer, malware remover, and other useful features.
* **GrandPerspective:** A free and open-source tool that creates a treemap visualization of your disk usage.
* **OmniDiskSweeper:** A free utility that quickly scans your drives and lists files from largest to smallest.

**How to Use a Storage Analyzer Tool (Example: DaisyDisk):**

1. **Download and Install:** Download and install your chosen storage analyzer tool.
2. **Launch the Tool:** Launch the application.
3. **Select Your Disk:** Select the disk you want to analyze (usually your Macintosh HD).
4. **Scan the Disk:** Click the **Scan** button. The tool will begin scanning your disk and analyzing your storage usage.
5. **Explore the Results:** The tool will present a visual representation of your storage usage, often in the form of a disk map or a list of files and folders, sorted by size.
6. **Identify Large Files:** Identify the largest files and folders, particularly those that seem unnecessary or that you can move to external storage.
7. **Delete or Move Files:** Use the tool to delete or move the identified files and folders to free up space. Be cautious when deleting files, and only delete files that you are sure you don’t need.

**Caution:** As with any third-party software, download storage analyzer tools from trusted sources to avoid malware. Some tools may require administrator privileges to access certain system files.

Method 8: Resetting NVRAM/PRAM (Less Common, but Potentially Helpful)

NVRAM (Non-Volatile Random-Access Memory) or PRAM (Parameter RAM) stores certain system settings, such as sound volume, display resolution, startup disk selection, and time zone information. Occasionally, corrupted NVRAM/PRAM data can contribute to storage-related issues. Resetting NVRAM/PRAM can sometimes resolve these issues.

**How to Reset NVRAM/PRAM:**

1. **Shut Down Your Mac:** Shut down your Mac completely.
2. **Locate the Keys:** Identify the following four keys on your keyboard: **Command (⌘)**, **Option (⌥)**, **P**, and **R**.
3. **Turn On Your Mac:** Turn on your Mac, and immediately press and hold the **Command-Option-P-R** keys simultaneously.
4. **Hold the Keys:** Continue holding the keys until the Apple logo appears and disappears *a second time*. On older Macs, you may hear the startup chime a second time.
5. **Release the Keys:** Release the keys after the second startup chime or the second appearance/disappearance of the Apple logo.
6. **Adjust Settings:** After your Mac restarts, you may need to adjust some of your system settings, such as sound volume, display resolution, and startup disk selection.

**Note:** The NVRAM/PRAM reset process is slightly different on Macs with Apple Silicon (M1, M2, etc.) chips. On these Macs, NVRAM is automatically reset if necessary during startup. You don’t need to manually reset it.

Method 9: Reinstalling macOS (A Last Resort)

If you’ve tried all the other methods and your system storage is still excessively high, reinstalling macOS might be the only option. This will erase your entire hard drive and install a fresh copy of macOS, effectively removing any lingering system files, caches, and other data that are contributing to the problem.

**Important:** Reinstalling macOS will erase all data on your hard drive. Make sure you have a complete backup of your Mac before proceeding.

**How to Reinstall macOS:**

1. **Back Up Your Mac:** Create a Time Machine backup or use another backup method to back up all your important data.
2. **Start Up in Recovery Mode:**

* **Intel-based Macs:** Turn on your Mac and immediately press and hold the **Command (⌘)** and **R** keys until you see the Apple logo or a spinning globe.
* **Apple Silicon Macs:** Turn on your Mac and continue holding the power button until you see the startup options window. Click the gear icon labeled **Options**, then click **Continue**.

3. **Erase Your Hard Drive (if necessary):**

* In the macOS Utilities window, select **Disk Utility** and click **Continue**.
* Select your startup disk (usually Macintosh HD) in the Disk Utility sidebar.
* Click the **Erase** button.
* Enter a name for your disk (e.g., Macintosh HD).
* Choose **APFS** or **Mac OS Extended (Journaled)** as the format (APFS is recommended for SSDs).
* Click **Erase**.
* Once the erase process is complete, quit Disk Utility.

4. **Reinstall macOS:**

* In the macOS Utilities window, select **Reinstall macOS** and click **Continue**.
* Follow the on-screen instructions to install macOS. You may need to connect to a Wi-Fi network.
* Select your startup disk as the installation destination.
* The installation process may take some time.

5. **Restore Your Data (Optional):**

* After macOS has been reinstalled, you can restore your data from your Time Machine backup or other backup source.
* During the setup process, you’ll be asked if you want to restore from a backup. Follow the on-screen instructions to restore your data.

Preventing System Storage Bloat in the Future

Once you’ve successfully cleared your system storage, it’s important to adopt practices that prevent it from becoming bloated again.

* **Regularly Empty the Trash:** Make it a habit to empty the Trash regularly, especially after deleting large files.
* **Manage Downloads:** Organize your Downloads folder and delete or move files you no longer need.
* **Uninstall Unused Applications:** Uninstall applications you no longer use. Use a dedicated uninstaller app (like AppCleaner) to remove all associated files.
* **Clear Browser Cache:** Regularly clear your browser’s cache and history.
* **Archive Old Files:** Archive older documents, photos, and videos to external storage or cloud storage.
* **Use iCloud Storage Effectively:** Use iCloud Photo Library and iCloud Drive to store files in the cloud and optimize storage on your Mac.
* **Update macOS Regularly:** Keep your macOS up to date to ensure you have the latest bug fixes and performance improvements.
* **Consider Using a Cleaning Utility:** Periodically use a reputable Mac cleaning utility (like CleanMyMac X) to remove temporary files, caches, and other unnecessary data.

By following these steps and adopting proactive storage management habits, you can keep your Mac running smoothly and efficiently, maximizing its performance and longevity. Remember to always back up your data before making significant changes to your system.