How to free up storage on your Mac (and what System Data really is)

If System Data is consuming a huge chunk of your Mac’s storage, the fix usually involves clearing caches and removing old Time Machine snapshots. Open System Settings › General › Storage and look for the gray bar labeled “System Data.” This category can range from 10 GB to over 100 GB, covering cache files, system logs, Time Machine local snapshots, browser caches, old device backups, and other hidden system-level data that macOS groups outside standard categories like Apps or Documents.

The “System Data” label replaced “Other” starting in macOS Monterey; the contents are essentially the same. macOS does not break it down further, which is why the category feels opaque.

Clear caches and snapshots

1. Empty the Trash. Obvious, but often forgotten. Files sitting in Trash still occupy storage until you permanently delete them.
2. Delete local Time Machine snapshots. Time Machine creates hourly local snapshots even when your backup drive is disconnected. macOS deletes older ones automatically when storage runs low, but you can remove them immediately. Open Terminal and run:

   tmutil listlocalsnapshots /

   You will see timestamped entries like com.apple.TimeMachine.2026-06-01-143022.local. To delete a snapshot, enter:

   sudo tmutil deletelocalsnapshots 2026-06-01-143022

   Replace the date-time portion with the actual timestamp. Enter your password if prompted, then repeat for each snapshot you want to remove.

   If working in Terminal feels tedious—and it can be, since you have to repeat the command for every single snapshot—there are some excellent utilities that handle this for you. The best-known is DaisyDisk, a popular disk space analyzer that visualizes your storage and lets you reclaim hidden space. DaisyDisk provides a macro-level view and deletion of purgeable space, which mostly consists of local Time Machine snapshots, plus caches, sleep images, swap files, and other temporary system files. In the standalone version you can drag the snapshots item (or the purgeable space item) to the Collector and delete it like a regular file; note that this is partially limited in the Mac App Store edition because of Apple’s mandatory sandboxing, so that version asks you to run a provided script in Terminal instead.

   Another option is CleanMyMac from MacPaw, which includes a dedicated feature for exactly this task. CleanMyMac can thin Time Machine snapshots in a few clicks: open the app, click Performance > Scan, then click Run under Thin Time Machine Snapshots on the results screen. It’s a one-time-purchase or subscription app, and it’s also available through Setapp, MacPaw’s subscription service that bundles CleanMyMac together with over 260 other Mac apps.

3. Clear browser caches. Browsers accumulate cache quietly.
   • Safari: Go to Safari › Settings › Advanced, enable “Show Develop menu in menu bar,” then choose Develop › Empty Caches.
   • Chrome: Open Settings › Privacy and security › Clear browsing data, select “Cached images and files,” and click Clear.
4. Clear app caches. App caches live in ~/Library/Caches. In Finder, hold Option and click the Go menu, then select Library. Open the Caches folder and look for folders from apps you recognize (Spotify, Slack, etc.). Delete the files inside each folder, not the folder itself. Common offenders: Spotify stores downloaded music here if streaming quality is set high; Xcode caches derived data that can reach tens of gigabytes.
5. Remove Xcode derived data (if applicable). Go to Xcode › Settings › Locations. Click the arrow next to the Derived Data path to open the folder in Finder. Select all contents and move them to Trash. Xcode rebuilds what it needs on next compile.
6. Check for large log files. System and app logs live in ~/Library/Logs and /Library/Logs. They are usually small, but a misbehaving app can write enormous log files. In Finder, switch to list view and sort by size to spot outliers.

What not to delete

• Anything in /System or /Library at the root level.
• Swap files (virtual memory). macOS manages these automatically.

Unless you know exactly what you’re doing, avoid “Cleaning” apps that promise to remove system files. They often delete items that look unused but are not.

Why System Data stays large

Much of the storage used by macOS for system-related tasks clears automatically, but sometimes that does not happen. Swap files and local snapshots will shrink on their own once your Mac has more breathing room. The parts you can control are caches and logs.

After clearing those, if System Data is still large, it is likely swap or snapshots that will resolve themselves over time. There’s no single “correct” size for System Data: it depends entirely on your hardware and how you use your Mac. On a machine with a large internal disk and a generously sized Time Machine backup drive, local snapshots alone can balloon to hundreds of gigabytes. APFS snapshots grow in proportion to the data you’ve changed or deleted, and during a backup a single snapshot can temporarily exceed 300 GB. So treat any fixed “healthy” figure with skepticism; what matters is the trend, not an absolute number.

What you can reasonably expect is that, after a cleanup, System Data should shrink. Just don’t expect it to happen instantly. macOS recalculates storage in the background, and that accounting isn’t a system priority: it can lag for several hours (or until the next reboot) while Spotlight re-indexes and snapshots are purged. If the number hasn’t budged right away, that’s normal; give it time before assuming something is wrong.

The most reliable way to free up space is to focus on what you can see directly: large files in Downloads, videos on Desktop, unused applications. Those tend to account for far more space than System Data does.