Why does System Data take so much disk space on Mac?

How much System Data is normal on Mac?

The default size of the macOS system is 12 GB. This implies that having around 12GB of system data is normal. Your operating system should automatically maintain and clear this category, but this doesn't always happen, resulting in a loss of precious disk space and often being the reason why "System Data" takes up so much storage. 

However, if your "System Data" shows something around 14-20 GB, you have pretty good chances to slim it down to that original size. This is good news, but you'll have to delete some unimportant files.

How to clear System Data storage

2. Clean up system junk

It is possible to reclaim some space manually, but there is a much easier way — using CleanMyMac. It has a dedicated Cleanup tool that can remove cache and temporary files, resolve errors, and claw back space in just a few clicks. Here's how to use it:

1. Open the app and select Cleanup from the sidebar.
2. Click Scan. Wait for the scan to complete and click Clean.

As you will see, it can delete gigabytes of system caches (like outdated app data) and thus trim down the System Data size. It really is as simple as that — no digging around in system files or worrying that you might delete something important. It does it all safely and securely for you.

A great thing about CleanMyMac is that it lets you control what's going to be removed — just in case you want to double-check. To do it, click Review after the scan is complete. From the screen that opens, you will see all files selected for deletion. You can then deselect any files you want to keep. Once you're ready to say goodbye, click Clean Up, and they're gone.

Get started with a free CleanMyMac trial. 

3. Restart your Mac

Over time, your Mac collects temporary files, caches, and other unnecessary data that can take up valuable storage space. A quick restart helps clear out these files, reset your apps, and stop any unresponsive background processes. 

If you’re using a Mac with Apple Silicon, restarting not only clears clutter but also frees up memory, giving you an extra boost in speed. Go to the Apple menu and click Restart to start from a clean slate.

4. Remove cache files 

I'm not going to lie; doing this manually is a bit of a long-winded process. I hate to sound like a nagging mum, but I must say carefully double-check all files and folders before you delete something that could affect your system.

Here's how to check and delete storage "System Data" files:

1. Open a Finder window, and press Go > Go To Folder.

2. Paste the following command box ~/Library/Caches and press Return.

3. Scroll through your subfolders, press Command-I to see information on each folder, and send to the Trash/Bin what you no longer need.

You can also repeat this process for /Library/Caches to remove even more cache files and reclaim more space.

5. Delete log files

So, you removed caches to trim the System Data storage. There is another location to check for even more spectacular results — log files. Here's how to access it: 

1. Open a new Finder window.
2. Click Go > Go to folder. 
3. Type ~/Library/Logs/ and press Return.
4. Find what you want to delete and send these files to Trash. Research everything before deletion.
5. Repeat for /Library/Logs/

6. Remove old Time Machine backups

Believe it or not, your macOS keeps a local copy of your Time Machine backups. These should get automatically deleted when space is low, but sometimes they don't. 

You can reclaim storage by manually deleting these. Here's how:

• Open Finder > Applications > Utilities and open Terminal.

• Copy and paste in: tmutil listlocalsnapshotdates and press Return.

If you have any, you'll see a list of backups sorted by date. To delete them:

• Type in: tmutil deletelocalsnapshots xxxxxxx where you see 'xxxxxxx' this should be the name of one of your listed backups — press Return.

Repeat this for as many of the local backups as you want to remove. What I like to do is, after I delete one, check back in the Storage tab to see how much space you've reclaimed.

This can take a while, so hang in there.

Tip: Don't delete your local copies if you think you might need them in the future.

7. Delete application leftovers

Applications often store logs, caches, and other data on your Mac, and sometimes these files stick around even after you've deleted the app. Here's how you can check for leftovers:

1. Open Finder.

2. Press Command-Shift-G and enter this location: ~/Library/ApplicationSupport

3. Look for folders named after the apps you've removed. Delete any that you no longer need.

Tracking down these app remnants manually can be a hassle. With CleanMyMac, you can uninstall apps and clean up their supporting files completely. Plus, its Applications tool helps keep your programs updated with the latest security patches. Get your free CleanMyMac trial. 

8. Remove old iOS backups

If you use your Mac to back up your iOS devices, you may end up with unnecessary old backups. If you no longer need them, you can safely remove them. There are several different ways to do it, but the easiest one is within System Settings:

1. Open System Settings > General > Storage. 
2. Next to iOS backups, click the i icon.
3. Send anything you do not need to Trash by selecting it and clicking Delete. Make sure to keep the latest backup.

Have you already tried the outstanding dynamic screen savers feature introduced in macOS Sonoma? But did you know that they are downloaded as video files and can take up more than 20GB of space? You can remove them and re-download them later if needed. Here's how:

1. In the Finder, click Go > Go to Folder.
2. This time, use the following path and press Return: /Library/Application Support/com.apple.idleassetsd/Customer
3. Check if there are any large files in there and send them to Trash.

10. Empty the Trash

This one may seem obvious, but emptying the Trash/Bin can significantly reduce the System Data volume on your Mac. The Trash/Bin usually becomes a graveyard of unnecessary files and apps even if you turn on the option of emptying it automatically.

You have several alternatives here: 

• Click the Trash icon from Dock and select Empty Trash/Bin.
• Right-click the Trash icon and select Empty Trash/Bin. 
• Use CleanMyMac and its Trash Bins feature in the Cleanup tool. In addition to emptying the Trash/Bin, it also clears out the photo library and Mail trash, thus freeing up even more space.

What to do if system data keeps increasing?

Many users have noticed that Time Machine snapshots can cause System Data to grow. Usually, these snapshots are deleted automatically after 24 hours — only if Time Machine is running regularly, ideally every hour. If you suspect that snapshots are the issue, you can check and remove them manually:

1. Press Command-Space, enter Disk Utility, and open it.

2. In the sidebar, choose your Macintosh HD - Data volume.

3. In the Disk Utility menu, click View > Show APFS snapshots.

4. Select the snapshots you want to remove and click the “–” button.

If cleaning up snapshots doesn’t help, try updating your Mac. Installing the latest macOS update can clear out old system files and refresh your System Data automatically.

Hopefully, you're no longer wondering why "System Data" takes so much disk space on my Mac. Following these tips will help you get to the bottom of the huge storage conundrum of the macOS "System Data" and recover some space. And if you want more tips on how to free up System Data storage on Mac, check out this article.