Out of the box WAV files have limited tagging capabilities. However, MusicBrainz Picard or Mp3Tag can attach id3 tags to WAV files, including artwork. I have most of my albums in WAV and there are no issues with metadata.
The workaround. Convert WAV files to FLAC/ALAC, tag them, and reconvert them to WAV. This way you will retain all tags and covers.
There are many tools that can tag wav files these days. But your workaroud is not reilable because when converting from flac to wav the converter needs to peoperly understand how to convert the tags and most (Inc dbpoweramp) don’t convert all fields properly and you will lose some data.
Thanks for all your help guys. This has beaten me and I can no longer use Roon like this. I have uninstalled\reinstalled both Roon and Roon Server. I have checked the embedded tags and they are artist\album\album artist\genre\track\disc\year and artwork exactly as I had set them up. Cleared the cache, set library artwork to choose Roon, File and Best still nothing. Heck I even reinstalled windows 10 and tried it all again. I even converted the files back to Alac. iTunes, WMP, Musicbee, dbpoweramp and Tag Scanner all recognise the images. The artwork is there as when I open Roon it flashes up and I can see it then it returns to the grey squares. I’m done and give up, can’t see how I can renew my subscription when it’s like this. Cheers🍻
Have you tried updating the drivers for your graphics card? I don’t know if it will help - I’m not a PC user - but I’ve seen various threads where this was suggested as a way to remedy a variety of display problems on Windows. Might be worth a try.
Have you accessed Roon from another device such as a phone or tablet? Do you still get the same problem when doing so? I presume your core is on the WIN10 box?
Well, the drivers installed by Windows may not be the latest from the manufacturer. It is best to download the graphics drivers directly from the video card manufacturer. This is not saying that was your issue, just a general comment to not rely on a Windows update providing you with the best drivers.
Thanks to Rugby the solution to this has been found. Somehow the Logitech G-Hub software for my mouse was the culprit. A fix I would never have found and a very strange bug indeed. As soon as I uninstalled that software the album covers returned as normal. After weeks of pulling my hair out all is now normal.