TheTest.com

Storage Full — What to Do When Your Disk Is Almost Full

How to free up space fast when your computer says storage is full, and figure out what's taking up all the room

Your computer just told you the disk is almost full. Don't panic — you can usually free up several gigabytes in a few minutes without deleting anything important. The goal is to figure out what's eating your storage, clear the easy wins first, then decide if you need a deeper cleanup or more storage. For ongoing maintenance, see Disk Cleanup.

Run the Storage Test

See what's using your space:

  1. Open System Settings > General > Storage — you'll see a colored bar showing how space breaks down by category (Apps, Documents, macOS, System Data, etc.)
  2. Wait a moment for it to finish calculating — the bar fills in as macOS scans
  3. Click into any category for details and options to manage that specific type of storage

Quick wins (do these first):

  1. Empty the Trash — right-click the Trash icon in the Dock and select Empty Trash. This is the number-one overlooked space hog. Deleted files sit in the Trash until you empty it
  2. Clear Downloads — open Finder, go to Downloads (or press Option + Cmd + L), sort by size, and delete anything you don't need. Then empty the Trash again
  3. Clear browser cache — this can reclaim 1-5 GB depending on how long it's been. See Clear Cache for steps per browser

Find large files:

  1. Open Finder and press Cmd + F to start a search
  2. Click the Kind dropdown, change it to File Size, set it to is greater than, and type 500 MB (or 1 GB)
  3. Set the search scope to This Mac to search everywhere
  4. Sort results by size to find the biggest files — look for old disk images (.dmg), videos, Xcode archives, and VM files

Cloud storage offloading:

  1. Open System Settings > [your name] > iCloud > iCloud Drive and enable Optimize Mac Storage — this keeps only recently opened files on your Mac and stores the rest in iCloud, freeing up space automatically
  2. In Photos, go to Settings > iCloud and select Optimize Mac Storage to keep lower-resolution versions locally while full-resolution originals stay in iCloud

App caches and system junk:

  • macOS stores app caches in ~/Library/Caches — you can safely delete folders inside here, but apps will regenerate them. Check this folder's size in Finder (Go > Go to Folder, type ~/Library/Caches)
  • Check ~/Library/Application Support for apps you've already uninstalled — some leave behind large data folders
  • Xcode developers: ~/Library/Developer/CoreSimulator and ~/Library/Developer/Xcode/DerivedData can grow to tens of gigabytes. Delete these freely — they're rebuild-able
  • Time Machine local snapshots take space: run tmutil listlocalsnapshots / in Terminal to see them and tmutil deletelocalsnapshots [date] to remove specific ones

Frequently Asked Questions

Will deleting files break anything?▾

Emptying the Trash/Recycle Bin, clearing Downloads, and removing browser cache won't break anything — those are always safe. Be more careful with files in system folders like Library on Mac or AppData on Windows. If you're unsure about a file, search its name online before deleting. App caches regenerate automatically, so clearing them just means a slightly slower first load.

How do I stop getting the "disk full" warning?▾

The warning triggers when free space drops below a threshold (usually around 5-10% of total capacity). Free up enough space to get above that threshold and the warning goes away. For a long-term fix, either regularly clean up (see Disk Cleanup) or move files to cloud storage. If you consistently run low, it might be time for a larger drive or external storage.

Should I buy more storage or just clean up?▾

If your drive is under 256 GB and you work with large files (video, photos, development tools), more storage is the real fix — you'll keep running into the limit no matter how much you clean. If your drive is 512 GB or larger and you're suddenly full, cleaning up usually reveals a specific culprit (old backups, cached media, forgotten downloads). Start with cleanup, and if you're still tight after a thorough pass, it's time for more storage.

What is "System Data" or "Other" storage on my Mac?▾

This category includes caches, logs, app data, Time Machine local snapshots, and anything macOS can't neatly classify. It often grows to 20-50 GB or more. Time Machine local snapshots are the most common cause of a surprisingly large "System Data" — they clear automatically when space is needed, but you can manually remove them with tmutil deletelocalsnapshots [date] in Terminal. Restarting your Mac can also reduce this category by clearing temporary files.

Is it safe to use "Storage Sense" or "Optimize Storage" features?▾

Yes. Windows Storage Sense and macOS Optimize Storage are designed to be safe — they remove temporary files, old update data, and files you can re-download. The iCloud and OneDrive optimization features keep your files accessible in the cloud and only remove the local copy when space is needed. You can always re-download files when you need them, as long as you have internet access.