I upgraded my MacBook to Catalina last night and it had some frankly disastrous results on my home setup.

* None of HK connected devices work from Mac - all show No Response but work fine on iPhone / iPad.
* Scenes have changed - most devices in scenes have disappeared.
* Most automations have disappeared, especially those involving motion sensors, but I think others have disappeared as well.
* I can't make any changes using the MacBook. I can't fix scenes or recreate missing automations. I need the iPad or iPhone for this.

The weird thing is that even though most of my automations disappeared from the iPhone and iPad, they were still on my Mac. But since it would not sync these automations with hub (Apple TV or HomePod) and I could not make any changes, it was as if it was not properly connected. I've turned HomeKit off and on in the iCloud section of System Preferences, but this didn't help. In fact, it made most of my scenes disappear from the system. I also tried logging the entire MacBook out of iCloud so everything could be synced from the cloud when logged in again, but that didn't help either.

I really would like to have figured this out before I put all my automations and scenes back to normal, but if I can't, I'll leave my Mac out of the HomeKit world. Do you have any ideas about this?