Now all devices unresponsive. Hard reboot on hub. Reboot radio. Rebuild network.
Nothing.
Seriously, what gives. I do an update this afternoon and this is the result?
Error logs full of retries to turn stuff on and off on the zigbee radio with failures. Zero devices found. Can't rebuild the network because zero devices found. Can't change the channel and power settings. Can't power cycle the radio.
No motion sensors. No switches. No outlets. None of it works.
My next thought would then be a bad device or the Zigbee radio has given up the ghost. I don't believe it's caused by the update (or the forum would be full of cases like yours) but the update could have exposed the issue during the reboot process.
I'm out of ideas. I think you definitely need staff intervention to review the engineering logs. If you have hub protect I would initiate the process for a replacement hub.
My next thought was to reset the zigbee radio but I'd have to repair all my stuff which is not an insignificant ask. I'd want that guidance from support first, I'm hoping there's a less nuclear option first.
I don’t expect it will change anything, but in if I were at the point you are, my next step would be to swap the Z-Wave and Zigbee antennas… just in case one is defective.
Has something else changed in the 2.4 GHz spectrum around your Hubitat?
Also, has there been a change in the hub's PAN ID? That would create a situation very similar to what you describe. In addition, putting devices into panic mode (by the 30 min shutdown) will not permit them to rejoin.
I know of this to have happened a couple times in the past to other users. But I thought there were changes to the hub's zigbee stack to minimize the likelihood of it happening.
Also, tagging @mike.maxwell, who is Hubitat's SME for all matters related to Zigbee.
Nope, no spectrum changes. I am literally the only SSIDs my devices pick up. Perks of having no neighbors
That said, I did a radio reset and we are back in business. I have two of the old Iris V2 motion sensors that are being cranky about re-pairing so I will get to those later, but for right now everything has come back albeit slowly. I just did a network rebuild so we will see if that helps sort out some of the issues and slow response I am seeing in the mesh currently.
I'd really like to understand the why behind this at some point so I can avoid it in the future.
I use a bunch of old Lowes Iris v2 Zigbee sensors in my house as well. I have recently had a couple of issues adding new Iris v2 sensors to my C8-Pro hub. My solution has been to perform an orderly hub shutdown, remove power for about 15 seconds, and then power up the hub. I let things settle out after the reboot for about 5-10 minutes. Afterwards, I have been able to resume adding new Zigbee devices. This seems like a recent change in behavior for my hub...but to be honest, I have not been adding many devices over the past couple of years. Everything has been running very smoothly and most of the house was already instrumented with sensors. I recently had my carwlspace encapsulated, and I added some Centralite temperature and humidity sensors down there. That is when I noticed this behavior.
Hopefully, something as simple as the above will help you pair your remaining devices.
As far as avoiding this in the future - one thing I appreciate is Hubitat's Cloud Backups (via either the Hub Protect or Cloud Backup subscriptions). Since the cloud backups contain the contents of the Zigbee and Z-Wave radios, I rest a little easier knowing that if my hub fails (either completely, or similar to your hub's issue, ) I can restore a cloud backup and get things back to normal quickly. I haven't had to do this, except when upgrading from my C7 to C8, and then from my C8 to C8 Pro hubs. Everything went very smoothly during those upgrades, without having to re-pair my Zigbee devices.
