How to Free Up Space on an External Drive or SSD on Mac (2026 Guide)

Running out of room on a portable hard drive or SSD is frustrating, especially when you depend on it for backups, creative projects, or overflow storage. The good news is that you can free up space on an external drive on Mac without buying new hardware — most drives are carrying surprising amounts of recoverable junk. This guide walks through every category of space-waster, with exact steps for macOS Sequoia and Tahoe on both Apple Silicon and Intel Macs.

Why External Drives Fill Up Faster Than You Expect

External drives accumulate files from multiple sources over years: Time Machine local snapshots, app caches written directly to the volume, developer build artifacts, duplicate photo exports, and forgotten virtual machine images. Unlike internal storage, macOS does not run its own Optimize Storage pass on external volumes, so clutter builds silently. The result is a drive that reads "full" even though you cannot name the files responsible.

What Is Actually Taking Up Space? A Breakdown by Category

Before deleting anything, understand what you have. Open Disk Utility (/System/Applications/Utilities/Disk Utility.app), select the external volume, and note the used space figure. Then open a Terminal window and run:

du -sh /* 2>/dev/null | sort -rh | head -20

Replace /* with the external volume path, for example /Volumes/MyDrive/*, to see the top-level folders ranked by size. The table below maps the most common culprits to their typical locations on an external drive.

How to Free Up Space on an External Drive on Mac — Step by Step

Step 1: Empty the volume's Trash

macOS keeps per-volume trash folders. Files you deleted from the external drive are not gone until you empty Trash while the drive is mounted. Right-click the Trash icon in the Dock and choose Empty Trash, or press Shift ⌘ Delete. This alone can recover gigabytes on neglected drives.

Step 2: Remove macOS metadata and hidden folders

When a Mac-formatted drive is connected to other systems, macOS scatter files like .DS_Store and __MACOSX across every folder. Clean them with Terminal:

find /Volumes/MyDrive -name '.DS_Store' -delete
find /Volumes/MyDrive -name '__MACOSX' -type d -exec rm -rf {} +

Replace /Volumes/MyDrive with your actual volume path. These files are regenerated automatically by macOS and are safe to purge.

Step 3: Delete Time Machine snapshots stored on the drive

If the external drive is your Time Machine destination, old snapshots can consume tens of gigabytes. List them with:

tmutil listlocalsnapshotdates /Volumes/MyDrive

Delete snapshots older than a chosen date:

tmutil deletelocalsnapshots 2025-01-01

You can also open System Settings → General → Time Machine, click your backup disk, and use the Delete Backup option for specific snapshots via the Time Machine interface.

Step 4: Find and remove duplicate files

Photo exports and repeated backups are the single largest source of avoidable waste on external drives. Use Finder's built-in Smart Folder feature (File → New Smart Folder → Add Rule → Kind → Image) to surface images by type and size, or learn how to find duplicate files on Mac for free using dedicated tools that can scan an external volume directly.

Step 5: Prune developer artifacts

If you store development work on your external drive, look for node_modules folders and Maven caches. The command below lists every node_modules directory and its size:

find /Volumes/MyDrive -name 'node_modules' -type d -prune -exec du -sh {} \;

Remove a specific one with rm -rf /Volumes/MyDrive/myproject/node_modules. Maven local repositories (.m2/repository if you redirected settings.xml to the external drive) and Cargo registries (.cargo) follow the same pattern: safe to delete, rebuilt on the next build run.

Freeing Space on an External SSD Specifically

APFS-formatted SSDs support space sharing between containers, which means the free-space figure you see in Finder can differ from what Disk Utility reports. If the drive looks fuller than expected, open Disk Utility, select the physical device (not just the volume), and check the container's available space. To reclaim space from APFS snapshots specifically:

diskutil apfs listSnapshots disk4s1

Replace disk4s1 with the actual slice identifier shown in Disk Utility. Delete an old snapshot:

diskutil apfs deleteSnapshot disk4s1 -uuid <UUID>

On drives formatted as ExFAT or HFS+, no snapshot layer exists, so the used-space figure is always straightforward.

Checking for Large Hidden Files and Folders

macOS hides files starting with a dot by default. In Finder, press Shift ⌘ . to toggle hidden file visibility, then sort by size. In Terminal, this command shows the ten largest items including hidden ones:

du -sh /Volumes/MyDrive/.[!.]* /Volumes/MyDrive/* 2>/dev/null | sort -rh | head -10

Common surprises: an old .Trash folder that did not get emptied, a .Spotlight-V100 index that grew unchecked, or a .fseventsd log directory. All of these are metadata that macOS recreates — deleting them is safe.

Auditing the Whole Drive Efficiently

Manually running Terminal commands across a large external drive takes time, especially when files are scattered across dozens of nested project folders. A tool like understanding what is taking up space on your Mac is a good starting point. For a faster pass, a tool like Crumb can audit all of these categories at once — hidden files, duplicates, developer caches, and orphaned app data — and show you exactly what is safe before you delete anything, even when the volume in question is an external drive rather than the internal disk.

Preventing External Drive Clutter Going Forward

A few habits keep external drives lean over the long term:

• Set a Time Machine retention limit. In System Settings → General → Time Machine, use the Options panel to cap how many backups are kept. macOS Tahoe offers finer-grained retention policies than earlier versions.
• Run npm ci instead of committing node_modules. If you version-control projects stored on an external drive, add node_modules/ to your .gitignore so those folders are never treated as permanent.
• Eject cleanly. Always use Finder's eject button or ⌘E before unplugging. Unclean unmounts cause macOS to write larger-than-normal recovery logs on the next mount.
• Reindex Spotlight periodically. A corrupted Spotlight index on an external drive swells the .Spotlight-V100 folder. Drag the volume into the Spotlight Privacy list in System Settings, wait ten seconds, then remove it — this forces a clean rebuild.
• Delete virtual machine snapshots before archiving. VM snapshots are disk-image diffs; they compound over time and are rarely needed once a project is inactive.