macOS 15 iPhone Mirroring Bug

iPhone notifications stopped appearing on my Mac long before I used Migration Assistant to move to my new M4 Studio; I don't think they've worked for me under Sequoia at all. I can't recall now if they broke when upgrading to Sequoia, or iOS 18, or if they had already stopped working before either of those.

Not sure if it is the same cause. One may try the workaround/fix below:

https://discussions.apple.com/thread/255854431?login=true&sortBy=rank

I just realized that the same was happening to me right as this popped up in my feed.

The following worked for me to get things working again:

In the iPhone Mirroring app on the Mac, open "Settings" and click the "Revoke Access to [iPhone]…" button (I had to quit and re-open the application to get this button to be active). You then get the setup screen and can set up mirroring again, which will then ask for notification mirroring and set them up so that they work and show up in th macOS Settings again.

I was a happy user of Migration Assistant for a long time, but some years ago encountered a problem that made me give up on it.

I had been having seemingly-random sync issues with a third-party notes app and Messages. Both turned out to have the same cause - a unique sync ID had been written to the app’s user defaults (using the default any host behavior), copied over during migration, and was now being used by multiple devices. Since the old machine was still in use, when each device asked the server for changes since the last time it synced it was sometimes getting incomplete data.

Getting the apps to generate new sync IDs fixed it, but this took a long time to figure out and I realized I was never going to be able to count on every third-party developer and team at Apple to think about stuff like this. Granted it’s supposed to be a migration not copy, but if I have to erase the old machine to keep using it then I might as well do a clean install on the new one.