Half of my devices gone after power outage

Hi, all!

After a power outage, almost half of my ZigBee devices were unable to re-join the network.
It’s a mixture of sensors and bulbs, funny thing is that several of them are actually SmartThings products.
I am running a v2 hub with the latest 29.8 firmware. I am trying to suspect the firmware update might have broken something, because if I remove a device, the hub is not able to redescover it anymore. :expressionless:
Any similar experiences? Any known fixes? If this is what I should expect from the hub after a power outage, it seems that it is time to look for a more stable hub (and manufacturer).

I have well over 200 zigbee devices on an v2 hub, and it’s very stable, so let’s dig into your situation a little more.

First, how long was the power outage? If it was 15 minutes or more, that caused your zigbee mesh to rebuild.

Next, how many devices are we talking about, and are any of them repeaters? If you don’t have any repeating capable zigbee devices, like mains powered switches or plugs, you will have problems if you have a lot of devices, and/or if they’re spread around your home.

Hi, John!

We are talking about 20 devices of these types: ST leak sensors, ST motion sensors, IKEA bulbs, Xiaomi leak sensors and Xiaomi motion sensors.

While ST might say that Xiaomi products are unsupported, I still find it very odd that their own sensors were not able to reconnect.

Based on the messages received by the hub, the power outage was about 10 to 15 minutes.
I am suspecting something changed at the firmware level, because about a month ago there was a 2 hours power outage, but all of my devices were fine after that.

Yes, there was a update in the firmware for improving something with zigbee if I recall correctly, but offhand I don’t know what that is. I’d probably submit a support ticket through the mobile app or email.

If I were you I’d add a repeater or two based upon the number of r devices you have. Since you have Xiaomi devices, I’d go with IKEA’s outlet for a repeater because from what I’ve read in the community those seem to work very well with those sensors.

I don’t have any of these sensors yet, but a quick search came up with a few posts. Maybe these can help you:


Thank you for the links!
As of support, that is the first thing I’ve tried, but it’s been 4 (working days) and I still don’t have a reply from them. In my experience during the last year, their support approach is also on a steep descending curve. :frowning:


It is a bit of a long shot, but have you addressed the possibility of interference from wi-fi? Just wondering if you were unknowingly vulnerable to it and a power outage caused the wi-fi channel to change to one that could cause issues. Might be worth ruling out as sooner or later someone else will ask the same question …

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Hi! It’s channel 6 for my Wifi vs channel 24 for ST ZigBee and channel 20 for Philips Hue. From what I read online, that should be okay, right?


Sounds as if It should be OK.

I think John is right though. You need some repairs to your Zigbee mesh. I suspect the power outage did indeed start a zigbee panic/heal and enough repeating devices were offline that downstream devices fell off. Your downstream devices can’t come back if the repeaters they were using are also not communicating properly. I had something similar a couple years ago and did this to fix it.

Start by powering off your hub and as MANY Zigbee devices as you can, including pulling the batteries If they’re easily accessible. If it’s a v2 hub. Pull its battery.

Let everything sit for 20 minutes. Then turn the hub on.

(this forces a zigbee panic/heal)

Go into the IDE. And enable insecure rejoin (temporarily, you can turn it back on later)

After that start with the devices closest to the hub and turn them back on one or two at a time. Think about the proximity of devices to the hub and turn them on in waves a few minutes apart starting with the ones closest to the hub. If any of the devices fail to come back up try to fix it before moving on to the next group. You should be able to re-add zigbee devices without deleting them first if they don’t automatically rejoin.

What you’re trying to do is force your Zigbee mesh to rebuild from the devices closest to the hub outward. Because you can’t really control how the mesh communicates you have to isolate variables by disabling devices you don’t want to be selected as potential repeating partners.

After you do that what does your system look like?

That method works well for Z wave, but it’s not always the best approach for zigbee because of the hard limit on the number of children that the hub can accept.

By having everything turned off except a single tier you pretty much force devices to try to choose the hub as a parent. And when they do that, the hub’s child slots fill up much sooner than if you had all the devices turned on.

As far as the OP’s problem, it does sound likely that some repeater somewhere, or maybe a couple of them, was either damaged by the power surges or just didn’t come online and that ended up with its perspective children trying to find other parents which then can block other child devices from finding a parent and all that.

It also sounds like the only repeaters they have are their IKEA bulbs. These are good repeaters, but only if they are on power. So my first question would be were all the bulbs on power at the point that you started trying to add things back?

Not being able to add a device is very frequently because you’ve reached the child limit somewhere. See the following FAQ:

FAQ: 32 Zigbee direct connection device limit?

So speaking as a former field tech, what I would do, is take the hub off power (including removing any batteries) and leave it off power for 20 minutes.

Meanwhile, go around the house and make sure that every single other Zigbee device is on power, including the IKEA bulbs. This is what will force them all into panic mode because the coordinator is off-line and will cause everybody To find new parents once the hub does come back online.

Once you put the hub back online, it may take a little while for everything to sort itself out. Maybe even a day. So just make sure everything stays on power during that time. The lights can be turned off from the app, just make sure they still have current.

Then see where you are the next day.

But the building out from the middle method works well for Z wave networks. Just not well for Zigbee networks. For example, suppose your hub is in your living room on the first floor. There are two zigbee pocketsockets on the floor above. Or in this case maybe two IKEA bulbs.

If you start building out in waves, you might start adding child devices that are along the first floor hallway, and they might be forced to attach to the hub as the only available parent. Where previously they would’ve used the IKEA bulbs on the floor above as a parent. This in turn might mean that the hub starts refusing to add additional child devices before you ever get around to turning the IKEA bulbs back on. :disappointed_relieved:

Anyway, zigbee is pretty good at self healing, but I would make as many repeaters available at once as possible, just in case the most effective network setup is to bounce out before coming back in.

JMO :sunglasses:


I will try that tomorrow and get back with feedback. Thank you for your support so far! :slight_smile:


Thank you everybody for your comments.
Unfortunately, the lost devices couldn’t be reconnected with any of the recommended approaches.
I managed to re-pair most of them manually until today.
What happened today? Nothing really. No power outage, internet connection didn’t drop, all devices were plugged in - then suddenly I lost again a couple of them (around 15 devices). SmartThings Support didn’t even replied after my first email so I am throwing this piece of crap in the garbage.