Hi, Its 2019 and I'm having the same problem. I couldn't get sync lock at all and was going insane when I pulled out the USB cable connected to my HX Edit laptop and it suddenly synced. I thought USB and SPDIF should work together. Having thought I had some sort of fix, I am getting incredibly low signal despite cranking everything up, i still had to normalise my test track and to cap it all, the sound is badly distorted, and not in a good way. I have raised a ticket but would be interested to know how anyone here may have overcome or solved these SPDIF issues.