A couple of updates on the above: I said above that this is a problem on Catalina. That was a typo: I meant Catalyst, and it only happens on Big Sur While trying to find a MacOS workaround we’ve found that it’s not the iCloud account that gets incorrectly used. Instead, where you have multiple Store accounts, one of them seems to gets picked arbitrarily So for example if you have one account set up for app / music / tv purchases, and another set up for book purchases, sometimes when you try to make an update to your music library it’s the music library associated with your book purchases that will get updated (if there is one) not the one associated with your music account. In this scenario, if there’s no music account associated with your book purchase account you’ll find that StoreKit will return the capabilities for this account (of which there will be none) rather than the capabilities of your music account. So the only workaround we have found for this so far is to tell Big Sur users that they must use the same account for music / app / tv / books. Not ideal.

Thanks, we’ll give it a try

We've now tried this on Monterey. There's still an issue but I think we learned a bit more: We created a fresh user account on the machine and logged-in to iCloud/Books/App Store/TV with an Apple ID which did not have Apple Music access. We logged-in to Music with an ID which had Apple Music access and enabled "Sync Library" from within the Music app At this stage, as before (on Big Sur), SKCloudServiceController().requestCapabilities denied that the user had ".addToCloudMusicLibrary" capability (even though they clearly had) Because the Apple ID we used for Music had not previously been used we opened the Music app and tried a variety of operations to make sure that they could play tracks / playlists / albums Ok and that we had the right authorisations. This was the same Apple ID we had used for our Big Sur testing As part of this we created a playlist in the user's library and then deleted it. Immediately after we did this, SKCloudServiceController().requestCapabilities started returning ".addToCloudMusicLibrary" capability So it seems as though creating an initial playlist in the account "kicked" it into life. Given that most of our users are new to Apple Music it's entirely possible that they have not created playlists before running our app, which might explain why we get this error so frequently. Unfortunately we only had the one spare Apple ID with unused Apple Music capability so we haven't been able to repeat the above steps to confirm. Now the account has started returning .addToCloudMusicLibrary it always seems to work on any machine. Also FYI we have not been able to reproduce the issue where we managed to create playlists in the wrong account on Monterey, which is definitely progress.

Sysdiagnose is attached to FB9191110 (currently uploading). Note that, as described above, we're not able to reproduce the issue now that the account in question has some actual content in it's library. As a result I'm not sure the sysdiagnose will be very useful.

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Just to confirm, I tried this again but this time allowed Xcode to do it's automatic build numbering thing. Same error - it seems to be completely broken. Automatic build numbering doesn't seem to be the cause, and nor does it seem to help.

Could someone from Apple please respond? This is really quite painful and means that the new auto-build numbering feature in Xcode 13 simply doesn't work on Catalyst apps, as far as I can see: it fails 100% of the time to generate valid build numbers. To summarise, this is how I've released an app for the last year: Increment the build number & version in my project, then check-in Archive & upload my iOS version Archive & upload my macOS version As of yesterday the process seems to be: Increment the build number & version in my project, then check-in Archive & upload my iOS version Increment the build number in my project again, then check-in again Archive & upload my macOS version Update a spreadsheet so that I can keep track of which iOS & macOS builds are equivalent I haven't started to think about what this means for labelling releases in source control or tracking issues across builds. None of this is good though. If this is intentional and there's a workaround at our end, please share it.

This looks a bit like this problem: https://developer.apple.com/forums/thread/693838 It started yesterday.

Thanks - seems to be working for me now. I was just able to upload an iOS & macOS build which had the same build number for both (from Xcode).

Definitely working Ok for me. This was from a few minutes ago, from TestFlight: I've uploaded lots of builds this week and haven't had a repeat of the problem.

Has anyone found a fix to this? I just posted a question on a couple of ASWebAuthenticationSession issues I'm seeing and just realised that one of them looks a lot like this one (apologies for the duplicate if so).

This earlier thread looks to be the same as my 2nd issue. It's currently unresolved though.

Could someone from Apple please comment on this?

It's been working fine for me for the last few months. In fact I just uploaded a new build of my catalyst app today, with the same version & build number on iOS & macOS. Incidentally I now let Xcode manage build numbers for me.

Wasn't working for me but just tried it a few seconds ago and it worked. However I then tried to upload the Catalyst version of my app and it's now broken again. Seems like the service is going up & down.