RESOURCES chevron_right MACOS 15 SEQUOIA

How to Reduce System Data on macOS Sequoia: Fix 100GB+ Bloat

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The Dusty Team

Mac storage guides

calendar_today September 25, 2026
schedule 6 min read
bolt Quick Answer (How to Clear System Data on macOS 15 Sequoia)

To reduce System Data on macOS Sequoia: 1. Run tmutil listlocalsnapshots / in Terminal and delete stale snapshots via tmutil deletelocalsnapshots [date]. 2. Clear user cache in Finder (~/Library/Caches). 3. Restart your Mac to flush purgeable swap and system logging daemon files.

format_list_bulleted Quick Navigation

1. What Changed in macOS 15 Sequoia Storage 2. Step 1: Purge APFS Local Snapshots 3. Step 2: Clean ~/Library Application Support 4. Step 3: Force macOS to Clear Purgeable Space 5. Safe Automation with Dusty

After updating to macOS 15 Sequoia, hundreds of thousands of Mac users have noticed their storage graph looking alarming: a huge grey bar labeled "System Data" taking up 60GB, 100GB, or even 200GB of their SSD. This continues the trend from earlier macOS versions where Mac storage is full of System Data, but Sequoia introduces unique caching behaviors that compound the problem.

info 1. Why Does macOS Sequoia Show So Much System Data?

In macOS Sequoia, Apple reclassified several hidden subsystems into System Data:

  • APFS Delta Snapshots: Time Machine takes hourly filesystem snapshots. Even if you delete a huge 50GB file, APFS holds the blocks until the snapshot expires.
  • Unified Logging & Crash Dumps: Sequoia's increased security logging accumulates gigabytes in /private/var/log.
  • Group Containers: Messaging apps like WhatsApp Desktop and Telegram store local media caches inside ~/Library/Group Containers.
  • Purgeable Storage: Cached assets that macOS promises to delete "when space is needed," though third-party software often encounters "Disk Full" errors before macOS triggers the purge (see our fundamental guide on how to free up space on Mac).

history 2. Step 1: Purge APFS Local Snapshots (Reclaim 20GB–60GB)

This is the single most effective fix on macOS Sequoia. Open Terminal and run:

# 1. Check if any local snapshots exist:
tmutil listlocalsnapshots /

If you see entries like com.apple.TimeMachine.2026-09-20-101432.local, delete them by passing the date stamp:

tmutil deletelocalsnapshots 2026-09-20-101432

Notice your available disk space immediately update in Finder.

Rather than manually typing snapshot IDs into the terminal, use our interactive macOS Cleanup Command Generator to generate safe shell commands for snapshot and cache management.

folder 3. Step 2: Clean ~/Library Application Support & Caches

To see which specific third-party applications are ballooning your System Data, run this diagnostic in Terminal:

du -sh ~/Library/Caches/* ~/Library/Application\ Support/* 2>/dev/null | sort -hr | head -n 10

This lists your top 10 largest folders. Often, you will discover that Google Chrome, Spotify, or Adobe creative apps (like Premiere Pro scratch disks) have left behind 30GB+ of cache in ~/Library/Caches. You can safely delete the contents of these specific app subfolders, or delete unused GarageBand sound libraries that Sequoia leaves in system folders.

restart_alt 4. Step 3: Restart Your Mac in Safe Mode

Booting macOS Sequoia into Safe Mode forces the operating system to perform automated filesystem repairs, purge kernel cache pools, and clear temporary swap storage:

  • Apple Silicon (M1/M2/M3/M4): Shut down your Mac. Press and hold the power button until "Loading startup options" appears. Select your drive, hold the Shift key, and click Continue in Safe Mode.
  • Log in, wait 2 minutes, and then restart normally.

Related Guides

Fix System Data Storage on Mac

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Premiere Pro Scratch Disk Full

Safely clear 100GB+ of media cache files without losing project assets.

Delete GarageBand Sound Library

Reclaim 30GB+ of hidden instrument packs and loops left on your drive.

WhatsApp Desktop Storage Fix

Purge bloated Group Containers media while safeguarding chat history.

auto_awesome 5. Fix System Data Automatically & Safely with Dusty

Manually navigating macOS Sequoia's hidden Library folders can be nerve-wracking. Deleting the wrong system folder can destabilize macOS or corrupt your apps.

Dusty for Mac takes the mystery out of System Data:

  • Categorizes System Data Components: Identifies developer caches, WhatsApp media, and orphaned app containers.
  • Plain-English AI Explanations: Connects to Gemini AI to explain exactly what each item is and its safety rating.
  • Trash-First Safety: Moves items to the macOS Trash with full reversibility.
  • Zero Subscriptions: Just $7.99 for a lifetime license.
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