what about your files via NAS ba? if so, connected to your AC wifi router? or your NAS power enough to list all the files or something like that?
I transferred the Minix Neo U1 to the HT room where I have wired connections to the router and the NAS, and Kodi was able to access the network drive immediately. So my issue must be caused by a combination of (slower than wired) wifi access and the relatively large, I assume, number of files (currently 118,xxx files in 6190 folders) in the NAS.
Some files don't output sound through the receiver though, even with the audio settings in Kodi for DTS, DTS-HD, pass through, etc, have been checked/toggled. Will investigate further.