This widget doesn't work properly in a multi server environment (https://www.outsystems.com/forums/discussion/38789/problem-in-multi-server-environment/).  In this topic it is recommended to use the Multiple File Upload component  (https://www.outsystems.com/forge/component-overview/200/multiple-file-upload).

It also has some security concerns, since it discloses the location where the file is stored on the server.