Bit late now but I've just put this build together myself. noticed a massive difference in speed in my setup from the 8700k z370 I had before the CPU failed. However there are no board drivers under 7.1.4 so no onboard NICs or sensors are working.
Having the same problem, fresh server & shares.
Seems to pick up 80% of the content even when deleting the library and starting from scratch. Seems to be no obvious connection between the media that is added and that that isn't.