I have a DS411j, my external USB drive (SATA, not USB 3) used to work perfectly for backing up. Now when I connect it it makes a repetitive ticking noise, it sounds like the disk being started and stopped constantly. When I plug the same drive into any laptop it works fine. I have also tried a USB key which is also not recognised and does not appear in USB devices. I am thinking there is a hardware issue with the USB ports or a software issue. I am running the latest update DSM.
Any ideas, or similar past experiences?