Dropbox: Moving Files to “Cloud-Only” Storage
Dropbox is a cloud storage service which replicates the files stored in the “Dropbox” folder of your computer to all other devices linked to the account. Because Dropbox is a “replica”, any files deleted from the local folder will be removed from the Dropbox account also. Therefore it is not possible to simply delete files from your local storage to free up space.
However, the Dropbox client has a feature called Selective Sync. This allows you to control which folders will be copied to your device, and thus makes it possible to keep files which exist in the Dropbox account (“cloud-only”) but not necessarily stored on all devices.
An existing folder of files can be moved to become cloud-only simply by using Selective Sync to exclude it from the local cache of files:
To reinstate the files, follow the same process but tick the folders you wish to include.