I held off upgrading to Catalina for a long time. I was hanging onto a few 32bit only apps and also I’ve experienced trouble in the past with new OS iterations. As we have reached 10.15.5 I decided to take the plunge and upgrade. We are running a few Macs in the house. Both MacBooks support Catalina natively, but my iMac is a 2009 model and as such is technically unsupported. I’ve been upgrading my 2009 iMac for a few years using the DosDude patch and it has always worked perfectly. The upgrade of the MacBooks went great, and even the iMac seemed to be coping well.
After a little use I noticed my CPU was constantly maxed out and I could also hear the HDD seeking a lot. Digging in I found 4 processes related to Apple’s new Music app running wild in activity monitor
The four processes in question where AMPArtworkAgent, AMPLibraryAgent, AMPDeviceDiscoveryAgent and AMPDevicesAgent. I assume from the naming of these processes that the first is used to download additional album and artist artwork, the second manages the library, the third looks for devices such as iPhones and Apple TV’s on the network and the fourth manages the wireless syncing of my old iPhone 4 in our kitchen dock which is used for music playback. The one that was causing the most trouble seemed to be the AMPArtworkAgent.
I had a look in my Music preferences and under the advanced tab I noticed that the Automatically Update Artwork tick box was checked. I unchecked this box to troubleshoot but still saw the process was eating up CPU cycles.
So last night I finally found a fix, but first a few caveats before you try this. My own library of ripped music is huge. I have 37k+ tracks stored locally & I used Cloud Music (formerly iTunes Match) to match and store them all safely in the cloud. I keep them locally because I listen to them all the time, I have the storage space, it allows me to continue to sync to my old iPod and iPhone, as well as play them back on my media centres and Sonos over NFS/SMB. Also, my iMac still works perfectly, but it is technically unsupported, so I went into this troubleshooting not knowing if it could be resolved given that the OS shouldn’t really run on my machine.
Anyway I finally managed to fix it & went the nuclear route.
1. Make sure the ‘Automatically Update Artwork’ check box remains unchecked in preferences > advanced.
2. De authorize your music app from apple. Head to Account > Authorizations >De-authorise within the music app toolbar.
3. Sign Out your Apple ID within music. Again Account > Sign Out.
4. Close the music app
5. Open Activity Monitor and search AMP. Force quit any processes beginning with AMP (assuming AMP is standing for Apple Music Player/process)
6. Go to your music folder and delete everything. Make sure you either have your own music stored in iTunes match or copy it onto an external drive for backup. This will delete any locally stored music, so if you don’t use match please do make sure you have backups of your own ripped music.
7. Go to the following folder and delete everything. This folder contains the SQLite that seems to control the artwork caches and also stores the artwork which Music caches from the embedded artwork in music files, probably to speed up UI rendering during playback/streaming.
8. Hold the option key and click on the Music icon to open the app. Keep holding option until a dialog appears regarding your music library. Opt to create a new library and call it Music (if it asks you to overwrite please do).
9. Once music opens, before you sign in with your Apple ID, go to preferences and make sure the checkbox for downloading artwork is still unchecked. This is a must or you will have the same problem.
10. Click on account in the top toolbar, sign in and reauthorise your music app.
11. You should now see your Apple Music start to populate (if you subscribe) and your iTunes match/cloud music start to return. It will take some time for the artwork cache to refill so be patient. AMPArtwork Agent and the other processes will run for a while, but this is simply to extract the artwork embedded in your music files and to populate the cache. Give it time and all of your artwork will come back.
12. If you use iTunes match, start playing your music or downloading your tracks again. The same goes for Apple Music. All should be well.
I still have the AMPArtwork agent process running, but it doesn’t get out of control. My artwork cache is now fully populated after around 8 hours of idling and use. Music is fast & snappy again and I can use it without issue. I’ve always managed my own artwork for my own ripped music, so I can do without the auto fetching of artwork from Apples Servers.
My own impression is that the process starts to loop. It is trying to extra artwork from the mp3/m4a meta of my own music files & also trying to populate the cache with additional artwork while trying to update my artwork (if the Automatically Download Artwork services is checked). The SQLite database must start to choke and the process runs amok. Mine is purring along again with around 85% idle CPU when using Firefox and music. Even on my unsupported workhorse iMac its working perfectly again.
I hope this post helps some of you out. One thing that drives me mad is wasted CPU cycles & HDD seeks/writes, especially to fluff out meta I’d rather control myself. Let me know how you get on.