How to Free Up System Storage on Your Mac

If you are looking for ways to speed up a Mac computer, clearing the internal storage is highly recommended. The main reason is that when your Mac runs out of storage space, it has to work harder to handle what little it has, which affects performance. Many people are often surprised when they go to System Settings > General > Storage to see what is filling up their Mac’s disk and discover that system data is taking up an unusual amount of space (sometimes over 100 GB). There are no clear official instructions or recommendations on how to erase it, but it’s much easier than you think.

The problem is that there is no exact definition of what system data is. These are simply a number of files that the system cannot clearly classify as an application, document, photo or video. These include temporary files that the computer intends to automatically delete later, app caches, files you’ve downloaded over time, iOS and iPadOS backups, and Time Machine snapshots (these are stored locally to restore recent versions of files when your external drive is unavailable).

To erase all non-essential system data, you can use a cleaner that will automatically take care of everything for you, or you can manually search for the data and process it bit by bit.

Before we get into the difficult way to clear system data, there are several apps that you can use to clear them in just a few clicks. A good example is OnyX, which is a safe and reliable Mac cleaning and maintenance utility. It’s free software, so all you need to do is download and install the correct version of OnyX for your version of macOS (for example, Tahoe or Sequoia) and run it.

Then, follow the following steps to clear system storage on your Mac using OnyX:

1. Open OnyX.

2. Select the Maintenance tab.

3. Make sure System, Applications, Internet and Others are enabled in the Cleaning section.

4. Click Run Tasks in the lower right corner.

5. Click Continue on the prompts warning you that OnyX will close all open applications and restart your Mac.

6. Enter your Mac password.

7. Click OK.

Don’t worry about the Applications button, because it won’t uninstall your apps. This will clear the default app cache. Application caches can become extremely large over time. When you delete them, apps will take longer to load since they have to rebuild their caches, meaning you’ll have to delete them again in the future. When you click the “i” next to Applications, you’ll see exactly what it removes. You’ll even see additional options you can enable to free up more space. Be sure to explore the other options (e.g. System and Internet) to maximize OnyX’s ability to clear system storage on your Mac.

Manually deleting files is one of the best ways to fix a slow Mac. One of the safest ways to do this is to use the Storage page in System Settings. Don’t delete anything under Applications, as this will remove the app from your computer instead of deleting its cache.

Follow these steps to clear system storage using the Storage page:

1. Go to System Settings > General > Storage.

2. Click the “i” next to Documents and delete any large files.

3. Particularly target the Downloads tab, where the remaining DMG files remain.

4. Click the “i” next to iOS Files or iPadOS Files and delete these backups.

5. Click the “i” next to Trash and click Empty Trash > Empty Trash.

You can also clear app caches manually – with much more control than via Onyx – targeting very large caches while keeping smaller ones, so that each app doesn’t have to rebuild its cache later.

Follow the steps below:

1. Open Finder.

2. Click Go > Go to Folder.

3. Type ~/Library/Caches and press Enter.

4. Press Command-J and check Calculate all sizes.

5. Click the Size column to sort the folders from largest to smallest.

6. Select all the largest caches.

7. Press Command-Delete.

Time Machine snapshots are also problematic, and here’s how to delete them.

1. Click System Settings > General > Time Machine.

2. Click Options.

3. Select Manually.

4. Click Done – local backups will be deleted in a few minutes.