Thank you for getting back on this, your time is appreciated.
I didn’t try your solution because yesterday I finally managed to get the music files populating again.
Unfortunately I suspect I may be experiencing the QNAP issue disscussed in:
I tried most of the workarounds there to no effect. What seemed to work eventually (after about the 8th time of trying) was to stop Roon in QNAP and uninstall it. Then ssh into QNAP and delete the RoonOnNAS folder recursively. Then reboot the NAS and also the network router, and re-install Roon on QNAP. (I also set Guest Access Rights to Read only for my RoonServer shared folders but don’t know whether that’s necessary).
Anyway Chris, Roon is functioning normally now and has survived a QNAP reboot following the firmware update to 5.0.0.2055