Running out of storage space on your Mac can be frustrating, especially when you’re not entirely sure where it’s all gone. You might have deleted large files or uninstalled unused apps, but still the “Your disk is almost full” warning keeps popping up. What gives?

TL;DR: Your Mac stores junk and temporary files in places you might not expect—log files, caches, mail attachments, and more can all eat up space over time. This article explores 12 often-hidden storage hogs and shows you safe ways to clean them. Use built-in macOS tools and a few tips from pro users to recover gigabytes of lost storage easily. Read and reclaim your Mac’s free space today.

1. Deep System Caches

System caches, which include everything from logs to temporary rendered files, can quietly consume gigabytes over time.

Where to find them: Navigate to ~/Library/Caches and /Library/Caches.

How to clean: Manually open each folder and delete files, or use a safe third-party cleaner like CleanMyMac or OnyX.

2. Application Support Files

Even after an app is deleted, its support files may remain. Apps like Adobe or Final Cut Pro store gigabytes of temporary project data long after use.

Where to check: ~/Library/Application Support.

Safe cleanup: Only remove folders for apps you’ve uninstalled or no longer use. Be cautious.

3. Old iPhone & iPad Backups in iTunes/Finder

If you’ve ever backed up your devices on your Mac, you might have years-old backups sitting around, silently hogging space.

Location:

  • macOS Catalina and newer: Finder > Select your device > Manage Backups
  • Mojave and earlier: iTunes > Preferences > Devices

Action: Delete old backups directly through the interface after confirming you no longer need them.

4. iMovie, Final Cut & GarageBand Libraries

Media-editing apps generate bulky temp files and preview renders. Even unused project files may remain hidden.

Places to look: Inside your Movies and Music folders and ~/Library/Containers.

Tip: Use the app’s “Manage Media” or “Delete Render Files” features when available to prevent manual deletion errors.

5. Mail Downloads & Attachments

The Mail app automatically stores every attachment you’ve ever received, even if you’ve already opened or saved it elsewhere.

Folder path: ~/Library/Containers/com.apple.mail/Data/Library/Mail Downloads

Cleanup: Delete safe-to-remove attachments or use Mail’s built-in options to reduce storage in Preferences > Accounts.

6. App Logs and Crash Reports

Certain apps continuously log actions, performances, and crash diagnostics.

Check here: ~/Library/Logs and /Library/Logs

Tip: These log files are usually safe to delete unless actively debugging errors. Clear them periodically.

7. Old Screenshots & Screen Recordings

It’s easy to forget how many screenshots and screen recordings pile up, especially if you use them frequently for work or sharing.

Likely folders: Desktop, Downloads, and maybe even Photos.

Suggestion: Search with Spotlight using kind:screenshot or .mov to locate and purge the bulk.

8. Language Files (Localization Files)

Your Mac stores language packs for dozens of languages you may never use. Good for universal support – bad for wasted space.

Where it lives: Within individual app packages, usually in .lproj folders.

Warning: Manually deleting these can break apps. Use tools like Monolingual to safely strip extra languages.

9. Duplicate Files

Photos imported multiple times? PDFs sent and re-downloaded? Duplicates are a major (and common) storage sink.

Detect & destroy: Try Gemini 2, DupeGuru, or Finder search with kind:document/kind:image and sort by name or size.

10. Trash Bin (Including External Drive Trash)

Emptying your Trash isn’t always one-and-done. Drives connected externally have their own hidden Trash directories.

What to do:

  • Right-click the Trash icon > “Empty Trash”
  • For external drives: Hold Option and choose “Empty Trash” for complete clearance

Note: Be absolutely sure before doing this.

11. Downloads Folder Overflow

The Downloads folder is notorious for accumulating tens or hundreds of forgotten items: DMGs, ZIPs, duplicate photos, etc.

Quick fix: Sort the Downloads folder by file size or date and remove old or unneeded items.

12. Time Machine Local Snapshots

Did you know that Time Machine makes local backups even when your external backup disk isn’t connected?

How to check: Use Terminal and run tmutil listlocalsnapshots /

To delete: Either wait for macOS to clean them automatically, or run sudo tmutil deletelocalsnapshots (snapshot-name) with caution.

Pro tip: Restart into Safe Mode — this often triggers macOS to clear snapshot caches.

Bonus Tip: Use Storage Management Tool in macOS

Apple provides a very helpful built-in tool to identify big files and optimize storage space.

Try this: Click the Apple Menu > About This Mac > Storage Tab > Manage.

Explore each section like “Documents”, “Mail”, “iCloud”, and you’ll see specific suggestions like storing files in iCloud, optimizing storage, and reducing clutter.

Final Thoughts: Regular Maintenance is Key

Your Mac doesn’t always let you know when junk files build up, so it’s good to schedule regular walk-throughs—maybe monthly. With tools like Finder, Terminal, OnyX, and Apple’s own storage manager, you can keep your system lean and running smoothly.

Make it a habit to clear out temporary, unused, or hidden files and you’ll rarely have to worry about a “Storage Almost Full” alert again!