Is the cover art missing on the albums view page and the actual album page, or grey box on the overview and the cover displayed when you go to the actual album page?
You might try increasing the memory for art in Settings/Setup.
Very strange indeed. I haven’t changed anything and now all my album covers are back on display. I don’t understand what happened. In any case thank you very much for your help.
I had this happen as well. I restarted Roon and everything was ok, but I’ve also had some weird search problems and general loading errors before restarting. Not sure what’s going on in the development area, but it’s been making Roon rather wonky as of late.