The quick fix: To clear massive “System Data” usage on a Mac, you need to delete old iOS backups, clear your browser caches, and remove leftover application support files. The easiest way is to use macOS’s built-in Storage Manager to delete large unused files, and then manually clear the `~/Library/Caches` folder.
## How We Researched
We analyzed macOS Sonoma and macOS 15 system storage allocation on a 512GB M3 MacBook Air, isolating exactly which hidden folders contribute to the vague “System Data” category.
## Table of Contents
– [What is System Data?](#what-is)
– [Step 1: Delete Old iOS Backups](#step-1)
– [Step 2: Clear the Caches Folder](#step-2)
– [Step 3: Remove Leftover App Files](#step-3)
– [FAQ](#faq)
What is System Data?
System Data (formerly “Other” storage) is a catch-all category that includes temporary files, app caches, old Time Machine snapshots, iOS device backups, and system log files. Over time, this category can balloon to 50GB or more.
Step 1: Delete Old iOS Backups
If you back up your iPhone or iPad to your Mac, those files take up massive space and are classified as System Data.
1. Open **Finder**.
2. From the menu bar, click **Go** > **Go to Folder**.
3. Paste `~/Library/Application Support/MobileSync/Backup/` and press Enter.
4. Delete the old backup folders inside.
Step 2: Clear the Caches Folder
Apps generate temporary cache files that often aren’t deleted automatically.
1. Open **Finder**.
2. Press **Command + Shift + G** to open “Go to Folder”.
3. Enter `~/Library/Caches` and hit Return.
4. Select all folders inside (Command + A) and move them to the Trash. (Do not delete the main Caches folder itself, just the contents).
5. Empty the Trash and restart your Mac.
Step 3: Remove Leftover App Files
When you drag an app to the trash, it leaves behind configuration files.
1. Navigate to `~/Library/Application Support/`.
2. Look for folders named after apps you have already uninstalled.
3. Move those orphaned folders to the Trash.
## Frequently Asked Questions (FAQ)
**Is it safe to delete files in the Caches folder?**
Yes. Your Mac and applications will simply rebuild the caches they need the next time you open them. Deleting them is completely safe.
**Why does System Data change in size randomly?**
macOS actively creates and deletes local Time Machine snapshots in the background. If you are low on space, the system will automatically purge these snapshots when you try to download a large file.
## Final Thoughts
Keeping your Mac’s SSD free of bloated system data ensures faster performance and prevents out-of-storage errors during software updates. How much space did you manage to reclaim by clearing your caches?