Dear friends , I made back up in my NAS Synology of the library just in case but after some days I have a power problem so the router went online again . When I tried to restore the library I saw that recovered only the movies on the internal sata in the device . All the other posts was a mess and I have to do it again...unfortunately BUT I cannot do it every time that I might have a failure either in the network or power down. What is the best method to backup the library and were (I mean a USB stick is better ?)