Mac Disk Full — Free Up Space and Optimize Storage Without Losing Files

Overview #

If your Mac suddenly slows down, apps won’t update, or you see the warning “Your disk is almost full,” it’s time to reclaim some space.
macOS needs at least 15–20% free storage to function properly — without it, Spotlight indexing, caching, and virtual memory all struggle, slowing your system dramatically.

Let’s fix it together by safely cleaning up hidden storage hogs and optimizing your drive without deleting anything important.

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Terms & Definitions #

Term	Definition
Purgeable Storage	Space macOS can automatically free (like iCloud files and caches).
System Data	Catch-all storage for logs, caches, and local backups; can grow excessively over time.
Other Volumes in Container	Separate partitions (like Recovery or APFS snapshots) that may occupy space invisibly.
APFS Snapshot	A read-only backup macOS creates during updates; safe to delete if old.
Optimize Storage	Built-in macOS feature that automatically removes watched movies, old emails, and redundant iCloud copies.

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Steps #

1. Check What’s Taking Up Space #

Let’s first identify what’s actually using your disk.

Steps:

1. Click the Apple Menu → System Settings → General → Storage.
2. Wait for it to load and view the color-coded breakdown: Apps, System Data, Documents, etc.
3. Click “i” beside each category for detailed file listings.

Terminal Command (Sorted List of Largest Files):

sudo find / -type f -size +500M -print 2>/dev/null

This lists files larger than 500 MB. You can adjust the size threshold (e.g., +100M).

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2. Empty Trash and Downloads #

It’s simple but surprisingly effective.

Steps:

1. Right-click the Trash → Empty Trash.
2. Open Downloads folder — delete unneeded installers, ZIPs, and DMGs.

Terminal Command:

rm -rf ~/.Trash/*

Emptying Trash and Downloads alone can free several gigabytes.

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3. Clear System and User Caches #

Caches speed things up — but old ones pile up quickly.

Steps:

1. In Finder, press Shift + Command + G.
2. Navigate to: ~/Library/Caches /Library/Caches
3. Delete old or large folders (leave critical app caches intact).

Terminal Command:

sudo rm -rf ~/Library/Caches/* /Library/Caches/*

Safe to remove — macOS will rebuild them as needed.

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4. Manage Large Files and Old Backups #

Find and delete old iOS backups, Xcode data, or large downloads.

Steps:

1. Open Finder → Go → Go to Folder…
2. Enter paths:
   • ~/Library/Application Support/MobileSync/Backup (iPhone/iPad backups)
   • ~/Library/Developer/Xcode/Archives (if you use Xcode)
3. Delete old folders manually.

Terminal Command (Find Large Folders):

du -h -d 2 ~ | sort -hr | head -20

Shows your top 20 largest folders in human-readable format.

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5. Remove Old Time Machine Snapshots #

Local Time Machine snapshots can secretly consume tens of gigabytes.

Steps:

1. Open Terminal.
2. Run: tmutil listlocalsnapshots /
3. Delete each snapshot manually: sudo tmutil deletelocalsnapshots <snapshot name>
4. Recheck space: df -h /

These snapshots are safe to delete once backups are completed.

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6. Delete APFS Snapshots and Logs #

If your drive still shows “Other Volumes” taking space, APFS snapshots may be lingering.

Terminal Commands:

sudo diskutil apfs listSnapshots /
sudo diskutil apfs deleteSnapshot -uuid <UUID>
sudo rm -rf /private/var/log/*

Each snapshot may free several GB. Always double-check the UUID before deletion.

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7. Clean iCloud Sync Caches #

Sometimes iCloud Drive files get duplicated locally even when marked as cloud-only.

Steps:

1. Open Finder → iCloud Drive.
2. Right-click → Download Now or Remove Download as needed.
3. Ensure “Optimize Mac Storage” is enabled:
   System Settings → Apple ID → iCloud Drive → Optimize Mac Storage.

Terminal Command (View iCloud Cache Size):

du -sh ~/Library/Mobile\ Documents

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8. Optimize Storage Automatically #

macOS can help you manage this proactively.

Steps:

1. Open Apple Menu → System Settings → General → Storage.
2. Click “Optimize Storage…”
3. Enable:
   • Store in iCloud
   • Optimize Storage
   • Empty Trash Automatically
   • Reduce Clutter

macOS will now automatically manage old files, watched videos, and mail attachments.

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9. Remove Old Language Files and Fonts (Optional) #

Many apps install unused localizations and fonts.

Terminal Command:

sudo rm -rf /Library/Fonts/*
sudo find /Applications -name "*.lproj" ! -name "en.lproj" -delete

This step is optional but can free 1–3 GB for heavy multi-language apps.

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10. Verify Disk and Reclaim Space #

Finally, run a quick disk check and trim command to reclaim free space.

Commands:

diskutil verifyVolume /
sudo trimforce enable

TRIM keeps SSDs efficient by cleaning unused blocks automatically.

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Conclusion #

You’ve cleared old caches, trimmed backups, and optimized iCloud storage — your Mac should now breathe freely again.
With at least 15–20% free space, macOS runs faster, Spotlight indexes efficiently, and app launches are noticeably smoother.

If space keeps filling up quickly:

Or consider using DaisyDisk or OmniDiskSweeper for a visual overview

Check for runaway log files in /private/var/log/

Limit Photos and iCloud sync