I am equally as frustrated and wondering why this is just coming to light now. I went back and forth with support for weeks while they supposedly looked at my logs and there was no mention of the unidentified albums being a cause. See the response I got to the new support topic I posted this week when I included the info about my unidentified tracks:
Nucleus is very slow and takes several minutes to reboot
This was never an issue before the advent of Roon 2.0 (at least not in my case - I had plenty of unidentified music before and no performance issues), so the product was certainly able to manage this well from the beginning until they went to cloud-based services, so while “Roon wasn’t ever built to be a file management system to handle large amounts of non-identifiable tracks”, it actually was able to at one time. Just maybe not intentionally? And there’s no mention of this in the marketing materials or FAQs. So I can’t help but think that they are justifying this issue which they only just found out about. Or else why wouldn’t they have made this point during the launch of 2.0?