I had a problem last night with trying to uninstall Emby from a new 920+ Synology NAS.
I initially installed Emby via manual install using package manager and all was initially working well.
I then tried to restore my settings from my current Emby windows install (using the backup and restore plugin), but it failed on the new NAS install and I could no longer get the web interface up and running.
I then uninstalled the package within package manager on the Synology as I wanted to