Why is Dropbox taking up space on Mac & how to fix it

Why is Dropbox taking up space on Mac? I had the same question on my own machine running macOS Tahoe a few weeks ago.

Dropbox is supposed to store files online, yet my Mac storage keeps shrinking. After a lot of testing in the sync settings, cache behavior, and a few overlooked features, the explanation became clearer for me. I’ll walk you through everything I found, and how to manage it the right way.

Why is Dropbox using so much space on Mac?

Dropbox works by syncing files between your Mac and the cloud. That sounds simple, but there are a few layers involved.

First, Dropbox can store downloaded originals locally. If you open or modify a file, the full version might stay on your Mac afterwards.

Secondly, the app maintains a local cache. This cache helps speed up syncing and recover partially downloaded files. Over time, especially with large transfers, it can grow quietly.

Finally, some files are marked as offline. When a file is available offline, Dropbox keeps a complete copy on your Mac.

The key distinction is this: some files are truly cloud-only, while others are stored locally even though they also exist in Dropbox. Understanding that difference is the first step toward fixing the problem.

Method one: Switch files to Online Only with Smart Sync

For most people, this is the easiest solution.

Dropbox has a feature called Smart Sync, which lets files stay in your Dropbox account but removes the local copy from your Mac. Here is how I change files to online only:

1. Open Finder.

2. Navigate to your Dropbox folder.

3. Right-click a file or folder and press Make Online Only.

The file remains visible in Finder, but the actual data sits in Dropbox until you open it again. When you double-click the file later, Dropbox downloads it automatically.

In my case, old project archives were consuming several gigabytes locally. Switching them to online only freed the space immediately.

If you want to review files before making changes, CleanMyMac’s Cloud Cleanup feature helps identify large cloud-related files linked to services like Dropbox. I sometimes use it to see which folders are worth moving to online-only status; here’s how:

1. Open CleanMyMac — get your free trial here (free for seven days).

2. Click Cloud Cleanup, then click Connect to Dropbox.

3. Click Scan and review the findings.

Method two: Clear Dropbox cache on Mac

Dropbox stores temporary sync data locally to speed up downloads and file updates, but as we all know, that cache can swell significantly.

On some older Mac setups, the cache folder still exists and can be cleared safely manually; here’s how:

1. Open up a new Finder window and press Shift + Command + G

2. Enter the following pathway:

• ~/.dropbox.cache

3. Open and delete the contents inside.

This removes temporary sync data only. Your real Dropbox files stay safe in the cloud and in your Dropbox folders.

If you’re running macOS Tahoe, this manual removal option is usually no longer possible. In that case, run the Cleanup feature from CleanMyMac instead. It scans hidden system and app cache locations across macOS, including ones users rarely check manually; here’s how:

1. Open the app and press Cleanup > Scan.

2. Press Review All Junk, search through the categories.

3. Remove unwanted junk by pressing Cleanup.

Method three: Change selective sync settings

Selective sync gives you another level of control. Instead of syncing everything, you can choose which folders remain on your Mac.

Here’s how:

1. Click the Dropbox icon in the menu bar, and press your name.

2. Select Preferences > Sync.

3. Next to Selective Sync, press Select Folders.

4. Uncheck folders you do not need locally.

Now, Dropbox will remove those folders from your MacBook but keep them in your cloud account. One important thing to mention here is never delete files directly from the Dropbox folder unless you intend to remove them everywhere. Dropbox sync means deletion on one device removes the file from all devices. Selective sync avoids that problem because it simply stops downloading the folder locally.

How to check how much space Dropbox is using

Open Apple menu > System Settings > General > Storage. Scroll through the storage breakdown and look for Dropbox-related data.

Or check inside the Dropbox app:

1. Click the Dropbox menu bar icon and click on your name.

2. Press Preferences > Sync & Storage.

That’s all on Why is Dropbox taking up space on Mac?

Frequently asked questions

Will making files online only delete them from Dropbox?

No. The file remains in your Dropbox account and can still be accessed from the web or other devices.

Is it safe to delete Dropbox cache?

Yes. The cache contains temporary sync files. Removing it does not delete your actual Dropbox documents.

Why does Dropbox keep downloading files again?

Opening a cloud file downloads it locally. If you mark it online only afterwards, Dropbox removes the local copy again.