Configure How Users Upload Items
You can decide whether you want users to be able to upload multiple files at one time on a per-enterprise and per-project basis. Multi-file upload is turned on as the default for any new enterprise, site, or project.
You can decide to allow a single-file upload for your entire enterprise or you can allow it for only some projects, adding more later.
If you decide to remove the ability to upload multiple files at one time, edit the container's configuration. In the Container Features Configuration window, remove Multi File Upload as a container feature.