This happened to me too initially.  After you installed Emby on DSM 7, did you shut it down through the Emby web interface (by pressing the shutdown button in Emby), or via the Synology Package Center (by pressing stop)?  I found that stopping Emby using the Synology Package Center did not actually work, and I had to shut Emby down via the web interface.  Once I did that, and re-ran the cp and chown commands over SSH, my users were restored.  The instruction video only shows stopping Emby via th