@Geoff_Mirelowitz – I get the metadata improver halted message when I switch cores (using a single license). Goes away on restarting Roon on the switched-to core.
I’ve assumed it is an authentication issue, which then causes the metadata service to balk at providing info to the new core. If that assumption is correct, then an authentication issue might be what’s causing it for you. But I suppose there could be multiple reasons for the metadata service to stall.
Not sure if that’s at all useful …
[See Switching daily between Roon core on work vs home computer? for a long-ish thread that mentions this issue, if you’re interested, although it won’t provide any solutions].