It was a zigbee switch (GE 45856) and at least 6-7 years old.
I had to turn off the main breaker because I removed a Sense meter from the panel. When I restored power, the switch was dead. No lights and can’t control out manually.
Funny thing is, I have an electrician coming in very soon to replace all my smart switches - we can toss this one in the trash.
Could have sworn I had a couple of these since the model number seemed familiar but it turns out mine are 43076. Use them to control a couple of fans and so far they've been rock solid. Looking them up also reminded me that they are Zigbee 3.0 which I had forgotten.
Of course they became obsolete almost immediately after I bought them last January; always wondered if there was some latent defect...
Just out of curiosity what are you replacing your switches with?
Almost every GE switch I had to go bad was exactly this same scenario. Apparently there is a Capacitor you can replace that fixes it. I thought about trying but almost all were old non z-wave plus devices and I decided I would rather replace them.
I'm using zigbee 45856 switches, all purchased Nov 2018-Mar 2019. A good number of them were 'like new' used for $15 on Amazon. IIRC, I had one dud when first installed, the rest (20-ish) are OK with a good number of power outages to test them.
RIP old dependable switcharoo! That was a good run for any outlet in my world! Good luck with the new switches. I hope they last as long or longer than old sparky there!