How to use Dropbox Smart Sync

Smart Sync is a feature of the Dropbox desktop app that allows you to make files online-only so you can save hard drive space on your computer. You can choose which files to make online-only or let automatic Smart Sync choose for you.

Note: The Smart Sync preferences you choose are unique to each computer and don’t affect other computers you use with Dropbox.

Set a file or folder to online-only or local

To set a file or folder to online-only manually, using Smart Sync:

1. Open File Explorer (Windows) or Finder (Mac).
2. Open the Dropbox folder.
3. Right-click the file or folder you’d like to set to online-only.
4. Hover over Smart Sync.
5. Click Online Only. If you’d like to save your file back to your computer’s hard drive again, click Local.
   

 Online-only explained 

If you’ve never turned on Smart Sync or set a file or folder to online-only, then all of the files and folders in the Dropbox folder on your computer are “local”. This means that they take up space both on your computer’s hard drive and in your Dropbox account and are available whether you’re online or offline. 

If you set a file or folder to online-only, you’ll still see the file or folder in the Dropbox folder on your computer, but it’s just a placeholder. You can only open it if you’re connected to internet. Dropbox removes it from your computer’s hard drive, so that it only takes up space in your Dropbox account online.

Anytime you open an online-only file, Dropbox automatically changes it to be “local” again, but you can change it back to online-only at any time.

Smart Sync vs. selective sync

Selective sync also helps you save hard drive space by removing files from your hard drive so that they’re online-only. However, those files will no longer appear in the Dropbox folder on your computer.

Automatic Smart Sync

You can turn on automatic Smart Sync so that files that you don’t open from your computer for a few months become online-only automatically and new files you add online become online-only by default. That way, the files that you don’t regularly use won’t take up space on your computer.

To turn on automatic Smart Sync:

1. Open your Dropbox desktop app preferences.
2. Click the Sync tab.
3. Under Save hard drive space automatically, select On. 
   • If you’re on a Dropbox Business team, and you prefer your admin manage this setting for you Let my admin manage this setting.

Note: If an application on your computer needs a file to be local to function properly, automatic Smart Sync will set it to local temporarily and return it to online-only later.

Set files you add to web to online-only by default

To make all files that you add to dropbox.com online-only by default:

1. Open your Dropbox desktop app preferences.
2. Click the Sync tab.
3. Click the dropdown next to Files added on web default and click Online-only.
   • If automatic Smart Sync is on, you can’t choose this option because your files already default to online-only.

Why do online-only files still appear to take up space?

Online-only files take up a small amount of space on your hard drive because the placeholder requires space to store the file name and the shortcut to dropbox.com, but it takes up much less space than the file itself would.

If you’re using Smart Sync with macOS High Sierra 10.13 and up, you may notice that online-only files appear to take up space when you try to manage storage space in your Mac settings.

The reason for this is that file size is calculated based on something called “logical size” rather than “physical size”.

To see which files are really taking up your storage space, adjust your Dropbox settings so that online-only files have both logical and physical size set to zero. To do so:

1. Sign in to dropbox.com.
2. Click your avatar (profile picture or initials) in the top-right corner.
3. Click Settings.
4. Toggle Smart Sync update for Mac on.
   • Note: This setting may take some time to update. If you don’t see the update reflected after a few minutes, close the Dropbox desktop app, then reopen it.

System requirements for Smart Sync

Mac: OS X Mavericks (10.9)

Windows: 8 and up

Note: You can’t use Smart Sync on a mobile device, but you can set your Dropbox files to be available offline on a mobile device.