I just recently started having this issue as well. Same message as the above.
I have my local files on a QNAP NAS, but my Roon Core is installed on a Windows 10 desktop. I do not know when it first happened, but I do know that I did not first notice until this past Thursday, when two unrelated things happened at essentially the same time:
I rebooted my Windows Desktop and in the process Windows pushed an OS update on me.
Coming up out of that reboot I discovered the “network crash” thing that happened with Roon, where my streaming services wouldn’t load within Roon (but albums that I’d added to my library already from Qobuz or Tidal would continue to play fine), and I couldn’t get signed in to the forums and read/post about what was happening (for a while I was trying to determine if the new OS update had broken Roon; came to learn the two things were unrelated).
Blockquote I think Timothy is right. Every time my network crash I have to restart Roon server to fixed the problem. I do not have to restart the core, just server. It not too bad to fix the problem for someone not have a lot of files. I have over 100000 flac and dsd files, take about 35 minutes.
I just tried to put this theory to the test. I rebooted my QNAP (where I store my local files). While it was rebooting, I closed Roon (“x’d out”), but I did NOT reboot my Windows Desktop (which Roon runs on). Once the QNAP rebooted, I reopened Roon. The error message is gone, and new metadata is once again loading correctly.
FYI.