Figure: preview and share option for link share
If you share an album or folder via the myCloud sharing window, you will see a preview with the option «Recipients may add their own content». If the link recipients then upload files, they will be stored in your myCloud account and are available immediately to anyone who has received the share link.
Would you like to disable the «Add files» function? You can disable this option on myCloud.ch at any time or remove the share completely. More information on sharing files in myCloud can be found here.