Why Does Dropbox Still Take Up Mac Storage When Your Files Are Set to Online-Only?

Why does Dropbox use storage when files are online-only?

Dropbox's online-only feature allows you to see your files in Finder without keeping their full contents downloaded on your Mac. For example, imagine you have a Dropbox account containing 200 GB of photos, videos, and work documents. You do not necessarily need all 200 GB stored on your Mac. When a file is online-only, Dropbox keeps it in your cloud account and displays a placeholder in Finder. The placeholder allows you to see the filename and access the file when needed.

This is a real problem reported by Mac users. In one Reddit discussion, a user found a hidden folder at ~/.dropbox/instance1/dfc consuming approximately 90 GB, despite the Dropbox files being configured as online-only. The user suspected that it contained local copies of recently accessed work sessions.

However, there are several situations in which Dropbox can still use local storage:

• Temporary downloads: Opening an online-only file downloads it to your Mac.
• Offline availability: Files marked as available offline remain stored locally.
• Sync cache: Dropbox keeps temporary data to support uploads, downloads, and syncing.
• File Provider data: Newer Dropbox installations use macOS File Provider infrastructure to manage cloud files.
• Recently accessed files: Files opened or edited may have local data associated with them until they are returned to online-only status or managed by the system.

This is why setting everything to online-only does not necessarily mean that every Dropbox-related folder on your Mac will immediately become empty.

Read more: Reddit: Dropbox taking up way too much storage despite online-only files · Dropbox Help: How to make Dropbox files online-only on macOS

1. Understand the difference between online-only and available offline

Before investigating hidden folders, check whether your files are actually online-only. Dropbox provides two main storage states: online-only and available offline.

Online-only: The file is stored in your Dropbox account rather than being fully downloaded to your Mac. You can still see its name and location in Finder, but you need an internet connection to open it.

Available offline: The file is downloaded and stored locally. You can open it without an internet connection, but it consumes space on your Mac.

Online-only placeholders can still use a small amount of local metadata storage. However, they should not occupy the same space as the complete original files. Dropbox also notes that opening an online-only file downloads it to your computer. You can then change it back to online-only when you no longer need the local copy.

Read more: Dropbox Help: How to make Dropbox files online-only on macOS

2. Opening an online-only file can download it again

This is one of the easiest ways to unintentionally increase Dropbox storage. Imagine that you have a large video project stored online-only. You double-click it in Finder to work on it. Dropbox downloads the file so that your application can access it.

After you finish editing, you close the project. However, closing the application does not automatically mean that the downloaded file has been returned to online-only status. The file may continue occupying local storage. If you regularly work with large Photoshop documents, video projects, audio sessions, or other large files, these downloads can accumulate.

How to return a downloaded file to online-only:

1. Open Finder.
2. Open your Dropbox folder.
3. Find the file or folder you no longer need locally.
4. Right-click it.
5. Select Make online-only.
6. Wait for Dropbox to finish syncing.

The file remains in your Dropbox account and can be downloaded again when needed. You can also choose Make available offline whenever you need a local copy. Important: The current Dropbox menu uses the terms Make online-only and Make available offline. Older guides and tutorials may still refer to these features as Smart Sync.

Read more: Dropbox Help: Make files and folders online-only

3. Find the hidden Dropbox cache folder

Dropbox maintains temporary cache data to support file transfers and improve performance. This can include files used while downloading, uploading, and syncing content.

On older macOS installations that do not use Apple's File Provider system, Dropbox stores this cache in a hidden folder named .dropbox.cache inside your main Dropbox folder. For a typical personal installation, the location is: ~/Dropbox/.dropbox.cache/. If you use a different Dropbox folder name, the path will be different (such as ~/Dropbox (Personal)/.dropbox.cache/).

How to find the hidden cache folder:

1. Open Finder.
2. Open your Dropbox folder.
3. Press Command + Shift + . (period) to toggle hidden files.
4. Look for .dropbox.cache.
5. Right-click the folder and select Get Info to inspect its reported size.

Why does the cache exist? Dropbox explains that the cache stores temporary files for performance and uses them as a staging area for uploads and downloads. For example, when you delete a large number of files from Dropbox, some temporary copies may remain in the cache rather than being removed immediately. Dropbox says this cache is automatically cleared every three days. If you need to recover storage sooner, its official support guide provides instructions for manually clearing it.

Read more: Dropbox Help: How to clear the Dropbox cache folder

4. Dropbox uses a different cache location on newer macOS installations

This is an important distinction. Newer versions of Dropbox use Apple's File Provider framework to integrate cloud storage with macOS.

Instead of placing the main Dropbox folder directly inside your home directory, File Provider installations place it under: ~/Library/CloudStorage/. You may see a folder named Dropbox or a Dropbox account-specific name there.

The cache location also changes. According to Dropbox, File Provider installations manage cache data outside the Dropbox folder, under a Group Containers location. The relevant directory has a name ending in .com.getdropbox.dropbox.sync. Inside that container, Dropbox documents a root-mount folder as the location to inspect when clearing cache.

How to check whether you use File Provider:

1. Click the Dropbox icon in your Mac's menu bar.
2. Click your profile picture or initials.
3. Open Preferences.
4. Select Sync.
5. Find Dropbox folder updates.

Dropbox will indicate whether you are already using File Provider or whether an update is available. You can also look for your Dropbox folder inside ~/Library/CloudStorage/. The folder location alone is a useful clue, but checking Dropbox Preferences is more reliable.

Read more: Dropbox Help: Expected changes with Dropbox for macOS on File Provider

5. Why did one Mac user find 90 GB inside a hidden Dropbox folder?

The 90 GB Reddit example is worth investigating because it shows why looking only at the visible Dropbox folder can be misleading.

The user found the following directory: ~/.dropbox/instance1/dfc. It reportedly contained approximately 90 GB of local data even though the Dropbox files were set to online-only. The user also explained that they regularly made large work folders available offline, edited them, allowed them to sync, and then changed them back to online-only. This is particularly relevant for people working with large media files, audio sessions, Photoshop projects, and video footage.

However, there is an important distinction. Dropbox's official documentation identifies .dropbox.cache and the File Provider Group Containers location as cache locations. It does not document ~/.dropbox/instance1/dfc as a universal folder that every Mac user can safely delete. Treat this Reddit path as an example of a storage location that one user discovered, not as a standard cleanup instruction.

How to check whether this folder exists on your Mac. Open Terminal and run:

If the folder exists and Terminal can access it, the command reports its size. This command does not delete anything. Do not remove the dfc folder just because it is large. First identify your Dropbox installation type, make sure syncing is complete, and consult Dropbox support before manually removing an undocumented internal data directory.

Read more: Reddit: Dropbox taking up way too much storage despite online-only files · Dropbox Help: What is the hidden .dropbox folder?

6. How to inspect Dropbox's hidden storage using Terminal

When macOS reports a large amount of System Data, it can be difficult to identify whether Dropbox is responsible. Terminal can help you measure the size of specific folders without deleting anything.

Check the older Dropbox cache:

Check the File Provider Group Containers:

The actual container name includes a unique identifier, so its exact name may differ between installations. Check the Dropbox folder itself under ~/Library/CloudStorage/ or directly under your home directory, and check available storage using:

Look at the Avail column to see the filesystem's reported available space. These commands help you narrow down where storage is being consumed. They do not guarantee that every Dropbox-related file will be visible or readable through Terminal.

7. How to safely clear Dropbox cache files

The correct cleanup process depends on whether your installation uses File Provider. Do not apply instructions written for an older Dropbox installation to a newer one without checking the difference.

Option A: Older Dropbox installation without File Provider:

1. Wait until Dropbox finishes syncing completely.
2. Quit the Dropbox desktop application completely.
3. Open Finder and open your Dropbox folder.
4. Press Command + Shift + . to show hidden files.
5. Open .dropbox.cache.
6. Move the files inside the cache folder to Trash. Do not delete the entire Dropbox folder.
7. Reopen Dropbox and allow it to finish starting and syncing.

Option B: Dropbox using File Provider:

1. Confirm that Dropbox has finished syncing.
2. Quit the Dropbox desktop application.
3. Wait for the DropboxFileProviderExtension process to stop.
4. Open Finder, select Go from the menu bar, hold Option, and select Library.
5. Open Group Containers.
6. Find the folder whose name ends in .com.getdropbox.dropbox.sync.
7. Open root-mount.
8. Follow Dropbox's instructions to move the cache files inside to Trash.

The Group Containers folder has a unique identifier, so its full name may differ between Macs. Do not delete the entire Group Container, the entire Group Containers directory, or unrelated Dropbox folders. Important: These instructions are for Dropbox cache cleanup. They are not instructions to erase the undocumented ~/.dropbox/instance1/dfc folder found in the Reddit example.

Read more: Dropbox Help: How to clear the Dropbox cache folder

8. Use Selective Sync when you do not need folders visible on your Mac

Online-only and Selective Sync are not the same thing. Online-only files remain visible in Finder, even though their contents are stored in the cloud. Selective Sync lets you choose entire folders that should not sync to your computer at all.

For example, imagine you have: 100 GB of archived client projects, 40 GB of old video footage, 20 GB of personal documents, and 5 GB of active work files. You might want the active files visible in Finder while keeping the archived folders out of your local Dropbox folder entirely. Selective Sync is useful for this situation.

Before excluding a folder, confirm that its contents have finished syncing to Dropbox online.

Read more: Dropbox Help: How to use Selective Sync

9. Prevent Dropbox from filling your Mac again

Clearing cache files can recover storage, but the problem may return if you regularly work with large files. A few settings and habits can make a difference.

Set new files to online-only by default: You can configure Dropbox so that newly added files in the root Dropbox directory start as online-only. Click the Dropbox icon in the menu bar, open your account menu, select Preferences > Sync > Default sync preference > Online-only. There is one detail worth remembering: Dropbox says this preference applies to new files added directly to the root directory. Files that already exist are not automatically changed, and documents created locally and moved into Dropbox can remain available offline.

Return completed projects to online-only: If you regularly work with large files, make a habit of changing finished projects back to online-only. Right-click the completed file or folder and select Make online-only. Check its sync status before assuming the local data has been removed.

Keep frequently used files available offline: Do not make every file online-only if you need to work without an internet connection. Keep important active projects available offline and return archived or completed projects to online-only. This reduces unnecessary downloads while keeping the files you actually need accessible.

Review Dropbox storage periodically: Every few weeks, check the Dropbox folder, hidden cache locations, and macOS storage overview. This helps you catch unexpected local data growth before it consumes most of your SSD.

Read more: Dropbox Help: Make files and folders online-only