DropboxΒΆ
While Dropbox supports the newer OAuth 2.0, ownCloud uses OAuth 1.0, so you can safely ignore any references to OAuth 2.0 in the Dropbox configuration.
Connecting Dropbox is a little more work because you have to create a Dropbox app. Log into the Dropbox Developers page and click App Console:

If you have not already created any Dropbox apps it will ask you to accept their terms and conditions. Then you are presented with the choice to create either a Drop-ins App or a Dropbox API App. Click Dropbox API App, and then check:
- Files and datastores.
- No – My app needs access to files already on Dropbox.
- All file types – My app needs access to a user’s full Dropbox. Only supported via the CoreAPI.
Then enter whatever name you want for your app.

Now click the Create App button. Under Status, do not click Development (Apply for production status) because that is for apps that you want to release publicly.
Click Enable additional users to allow multiple ownCloud users to use your new Dropbox share.
Note your App key and App secret, which you will enter in the External Storage form on your ownCloud Admin page.

Your ownCloud configuration requires only the local mount name, the App Key and the App Secret, and which users or groups have access to the share.

You must be logged into Dropbox, and when ownCloud successfully verifies your connection Dropbox will ask for verification to connect to your Dropbox account. Click Allow, and you’re done.

See Configuring External Storage (GUI) for additional mount options and information.
See External Storage Authentication mechanisms for more information on authentication schemes.