Are those albums from your personal music library? If so, the Sonos app might just be taking a while to load the album artwork files because of the size of the files and/or the size of your music library. Or there might be no album artwork associated with those music files.

Library artwork is fetched via the controller’s Associated Product. With a less-than-ideal network path -- extended/weak wireless hops -- this could run into latency issues.

The controller has very limited patience for library artwork. It will display -- and cache -- a blank. Force-quit of the controller and restart will often recover the missing art.

If the local library is outside the local subnet, addressed by IP, this can sometimes cause other issues.

Yes.  It's not a huge library.  Sometimes there are only a few greyed images, then on another occasion there are many.  It's not consistent. 

Where is the library stored?

Next time there’s a problem note the Associated Product IP and figure out which player is being used. You might see a pattern.

There's only one hop - music on router USB drive. 

What's an associated product? 

Look in Settings/System/About. The Associated Product is the node the controller uses to obtain information from the system, such as the library index. It also proxies requests and responses to obtain library album artwork.

If the Associated Product is a wireless node the round trip to fetch art from the router’s USB drive could require at least four hops over a not very good connection. 

If I understand you correctly then the ap is a connect.  Traceroute reports one hop. 

Traceroute? I’m talking of physical hops across SonosNet. 

Eh?  What does physical hops mean? 

castalla,

Controller → associated player → USB drive → associated player → controller.

Thanks. 

I had this issue with Sonos Album art, but also with my Sony Walkman player which was even pickier.

My solution was to use Mp3tag application to tidy up all my music.  I imbedded the album art onto each track of the album and problem solved.  Took a while to do my full collection but well worth it, I also used AlbumArtExchange website to update with decent resolution album art files.

Thanks for this.  I'll play around with mp3 tag. 

What puzzles me is that each attempt to view the library can result in different outcomes.  For example, run 1 displays with the art missing for the third album.  Run 2 has third album art displayed but missing for other albums.

There's no consistency or obvious pattern. 

In Music Library, selecting a category (eg. Songs) displays the content as a list WITHOUT any missing images. 

It seems the Album grid view is the offending component.  I suspect mediocre programming... 

So, here's a comparison of grid view for Sonos and the LMS controller - both access the same data. 

Guess which is the 200 dollar system and which is the 25 dollar one. 

My expectations that sonos will ever fix this are somewhat low. 

This was my issue. All albums had folder art but some would always fail, not just on my Sonos. The embedding, making sure the same art was imbedded for each track of the album, sorted all the issues. Sometimes the artwork is slow to appear though, that’s pretty rare and random now  though. 

Artwork delivery times will vary, depending on current network traffic and interference. I can also speculate that if the controller associates with an older SONOS player, delivery might be slower. Plus, the path through the SonosNet mesh could vary depending on the current network topology traversed by the associated player.

Same missing artwork on Roam. 

It doesn’t matter which room you’re controlling, the artwork gets fetched the same way: via the current Associated Product.

I’d say you have some wireless network issues with your Sonos nodes. The LMS controller obviously has a completely different path to the stored art.

Can you force change the Associated Product?

Esp. if the system has decided to use a Wirelessly connected one as opposed to a Wired one?

It’s not fixed. I believe it’s initially the first player to respond to the discovery when the controller cold-starts. Over time it may move around. 

All my sonos devices are wireless. 

On your WiFi, rather than SonosNet? That could be a factor. 

If you plug a cable into a WiFi connected system, it all should revert to a Sonosnet system I believe (although I have seen ‘mixed mode setups?)?

Is connecting a cable to a single unit an option (at least temporarily)?  Then the full close/re-opening of Controller.

Possible.... I'll have to check how easy that would be without buggering up the system.... My confidence in the Sonos matrix world isn't too strong!