50 GB in Dropbox, 50 GB on your disk — that's the default, and here's how to change it

Updated September 2026 · 7 min read

Dropbox is a reliable way to keep files in the cloud, but there's a detail that surprises many Mac users: by default, Dropbox downloads everything in your account to your Mac's local disk. If you have 50 GB of files in Dropbox, you have 50 GB of files on your Mac too — using real SSD space.

This is by design — it gives you offline access to all your files. But on a Mac with a 256 or 512 GB SSD, it can be a serious problem. Here's how to take back that space without losing access to your files.

How Dropbox uses your disk space

When you install Dropbox on Mac, it creates a Dropbox folder (usually in your home directory or in Finder's sidebar). By default, every file in your cloud account gets downloaded to this folder. That's the primary space issue — it's not cache or junk, it's your actual files, duplicated locally.

On top of that, Dropbox also stores:

• Cache: temporary files in ~/Library/Caches/com.getdropbox.dropbox — usually modest, a few hundred megabytes.
• Application Support: sync databases and metadata in ~/Library/Application Support/Dropbox.
• The .dropbox.cache folder: a hidden cache inside your Dropbox folder itself, used for conflict resolution and temporary downloads.

The fix: make files online-only with Smart Sync

Dropbox's Smart Sync feature lets you keep files in the cloud without downloading them to your Mac. The files still appear in Finder — you can see their names, browse folders, and open them — but they only download when you actually open them. This can save tens of gigabytes.

How to enable Smart Sync

1. Click the Dropbox icon in your menu bar.
2. Click your profile picture (or initials), then Preferences.
3. Go to the Sync tab.
4. Under Smart Sync, set the default to Online Only.

New files added to your Dropbox (from other devices or shared folders) will now remain online-only by default — they show up in Finder but don't use local disk space until you open them.

Make existing files online-only

For files already downloaded to your Mac:

1. Open your Dropbox folder in Finder.
2. Right-click a file or folder.
3. Choose Smart Sync → Online Only.

The local copy is removed, and the file becomes a cloud-only placeholder in Finder. You can still see it, search for it, and open it — Dropbox will download it on the spot when you double-click.

To convert large sections at once, right-click entire folders rather than individual files.

Selective Sync: an alternative approach

If Smart Sync isn't available on your Dropbox plan, you can use Selective Sync to choose which folders sync to your Mac at all:

1. Open Dropbox Preferences → Sync tab.
2. Click Choose folders to sync to this Mac.
3. Uncheck folders you don't need on this computer.

Unchecked folders are removed from your Mac entirely (they stay safe in the cloud). The difference from Smart Sync is that unsynced folders don't appear in Finder at all — they're only accessible through the Dropbox website or other devices.

Clean up the hidden cache

Dropbox keeps a hidden cache folder at .dropbox.cache inside your Dropbox folder (it's invisible in Finder by default). This cache is used for file conflicts and temporary operations and is supposed to auto-clean after a few days, but it sometimes doesn't.

To check and clean it:

1. In Finder, press Cmd + Shift + G and go to your Dropbox folder.
2. Press Cmd + Shift + . to show hidden files.
3. Look for .dropbox.cache — check its size with Get Info.
4. If it's large (over 1 GB), you can safely delete the contents. Dropbox will recreate the folder as needed.

Cloud storage apps like Dropbox are just one part of the disk-space picture. For a complete look at what else might be filling your Mac, see what's inside System Data.

FAQ

Does making Dropbox files online-only delete them?

No. The files remain safe in Dropbox's cloud. Only the local copy on your Mac is removed. You can still see the files in Finder and open them anytime — Dropbox downloads them on demand when you double-click.

How much space can I save with Smart Sync?

It depends on how much is in your Dropbox. If you have 50 GB synced and make most of it online-only, you could reclaim 40+ GB of local disk space. It's one of the biggest single space-saving moves on a Mac.

Why is Dropbox using disk space if I have Smart Sync on?

Files you've recently opened get temporarily cached locally. Also, files and folders explicitly set to "Available Offline" remain on disk by design. Check your Dropbox folder for items marked with a green checkmark — those are locally stored.